Deciding when to give up on an anime series is a process which varies greatly from person to person. Everyone has their own rule or internal metric by which they judge. When discussing this you'll hear people talk about their "two episode rule" or that "it jumps the shark when this happens enough times". My personal rule is "when it starts sucking".
I recently tested the waters of a series called "The Book of Bantorra", and didn't make it past the first episode. The episode wasn't awful, there were ups and downs, but overall it failed the "sucking" test. What follows is a series of points, in what is mostly a chronological sorting, as to what was good, bad, or neither about the episode.
Good: The opening scene. The episode begins with your classic scary white room, where a helpless and defeated subject responds to a disembodied voice. This trope is fairly common, and has been used in many different genres of cinema and television for years. The subject in the room is like a lab rat, essentially meaningless to the disembodied, detached voice that observes them. Control is clearly entirely in the hands of the one and not the other, a fact emphasized by the defeated and disheveled appearance and demeanor of the subject. It's a clear, effective way to communicate the relationship between two characters or groups.
This episode uses this setup to good effect. The subject eerily discusses the philosophy of love and humanity with a voice coming from a vintage record player. This broken shell of a person states clearly that humans are to be loved, humans in pain are to be comforted, and outcast humans are to be rescued. The incongruity between this stated philosophy and their passive, defeated state builds until the subject announces, when prodded by their invisible overseer, that they are not human. As is standard, the voice asks "What are you?", and the subject replies "I am a bomb". This is all classic stuff and well executed.
Bad: The scene doesn't end there. Normally this type of scene would end after the revelation of the full brokenness of the subject. They no longer believe themselves to be human, but have instead been twisted and corrupted into something both sorrowful and terrifying. Tension is usually generated or heightened by cutting away following the subject's disturbing statement that they are a weapon, not a person. This may be fairly cliche, but it's still effective when done correctly.
Instead of following the standard route, however, the conversation continues. The voice asks the subject for their purpose, and the subject responds that it's to kill some unpronounceable two word proper noun which seems to indicate some specific person, group or category. This statement is repeated several times as the scene fades to white and finally ends.
This extension, unfortunately, muddies the scene. Rather than leaving the audience with the tension created by the depravity of the situation, the effect is lost as instead the audience is now wondering what/who this "Hamyuts Whatsamigger" is, and why someone would create a human bomb to destroy it/them.
Moreover, it diminishes the effectiveness of the disembodied voice. The moment the subject answered "I am a bomb" control was clearly established. The voice, if anything, would have responded "Yes, you are a bomb" followed maybe by some statement indicating the subject is a good, obedient boy/girl and will be rewarded somehow, or some other equally twisted perversion of typical authority/subject roles. Instead, the voice essentially tries to reassure itself that the subject is fully under its control, continuing to ask questions which establish this. In doing so, the voice loses some of its certainly and security, and thereby its authority.
Overall the scene was still effective, but it lost much by being extended.
Bad: The story unfolds with villains discussing matter over dinner. This is another fairly classic method of introducing characters and their relationships. Several villains discuss their villainy, their deviant philosophies, and their plans over a lavish meal on a luxurious cruise ship, indicating their excess wealth and power. This is not, in and of itself, a bad choice. The tool being used here is both solid and standard, and is not by any means to be shunned.
However, in this case the tool is misused. Introducing villains is a tricky art with many traps, and many of them come into play here. The end result is a set of three flat and uninteresting villains who barely even register as evil.
The first trap is context, or the complete lack thereof. Villains need the context of the world within which they exist to stand out as villainous. You can try to build part of that world using villains, but laying foundations in this way is an extremely difficult proposition. If it wasn't for archetypes and character design, it would have been difficult to tell these were even villains.
The second is flow. We just left a scene in which a mystery voice exerted dominance over a hapless test subject in a nondescript room. It isn't uncommon to follow this up with a villain or villains gloating over their success or passively recording their observations and moving on to the next in a long series of meaningless victims, if you transition to the villain responsible at all. Transitioning to a completely unrelated dinner discussion of even more abstract philosophical matters which doesn't include clear villainy simply dulls the whole thing. Are these people villains or the most wealthy philosophers of the Ayn Rand school in the world?
Finally, the topic of discussion is largely that of "True Man", a term that means nothing to the audience before and after the conversation (much like that Hamyuts Whatchamawhosits from the first scene). When the conversation ends, the audience is left wondering what the deal is, and doesn't get any answers before the good guys attack.
Good: Casma dies. The good guys, including this Casma fellow, interrupt by attacking the luxurious cruise ship from a patrol boat. Casma fits the standard "lazy, irresponsible but ultimate true and faithful ally" archetype very clearly, as the attack opens with him complaining about how much he hates actually putting his obvious specialty to use. When a man falls overboard off the cruise ship after the opening salvo, Casma selflessly dives into the water to save him. Then the man explodes, presumably taking Casma with him. I assume Casma is dead because he was A) at point blank range and B) we don't see him for the rest of the episode.
I call this good because it's extremely surprising. Killing off a clear archetypal character before they've have 30 seconds of screen time is bold and interesting. The moment Casma lay hands down on the patrol boat panting and complaining about work it was clear that he'd be around as a semi-comic relief character, shirking duty and work until. The moment someone's life would be in danger, however, he'd show his true colors and prove truer than anyone else. That they killed him almost immediately, having spent time and resources to design his character as a clear primary cast member, made all the other heroes look more vulnerable.
Bad: No one cares about Casma. The full extent of mourning for Casma consists of one, and only one, character calling out his name, followed by a brief expression of anger and frustration. This is a surprising complaint coming from me, as I tend to dislike long, overwrought and extended sequences of mourning for dead characters. Some of my favorite anime moments involve characters dying suddenly in the heat of battle without a moment to grieve, as there isn't any time for that on a battle field. The reaction to Casma's death is simply lacking.
It essentially makes the rest of the heroes look inhuman. Nobody jumps in the water to try and rescue Casma, or what's left of him. Nobody clenches a fist, fights back tears, or makes plain their sorrow. We have one character and one character alone who even comments, making the other half dozen on board heartless monsters.
This might have been excusable, except no mention is made of it later in the episode either. Not when they complete the mission, not when they return to base to discuss the success/failure of the mission, not when they get their next assignments. Casma drops off the face of the episode, presumably resting in pieces, and no one bats an eye. It's a shame, as he's the only character who had a name which you could actually be expected to remember.
Bad: World building failure. The Book of Bantorra, like many anime, has its own world with somewhat different rules than the universe as we know it. When you die, for example, your soul crystallizes into a book (which looks like a stone tablet). This premise is the cornerstone for all the other interesting differences between real boring life and this story world. Discovering how these differences and the reasons behind them is one of the fun aspects of this type of story.
Guiding the audience through the process of discovery is not an easy task. Throw too much at the audience and they're overwhelmed by the infodump, too little and they're left in a murky fog which obscures any other redeeming qualities. In this case, the guiding hand behind this series managed to do both.
It starts with the Hamyuts Whosacallums and True Man proper noun drops I've mentioned before. It's not uncommon for anime to drop terms in this manner and for the audience to remain in the dark as to what exactly they mean. As part of the discovery process the audience comes to understand and accept them. In Book of Bantorra you end up with a half dozen of these in the very first episode alone, none of which are fully explained.
A good example is the term "Meats". The term is used pejoratively to describe people who have lost all will to live and don't even consider themselves to be human. We don't know why they've lost the will to live, why the cruise ship has a small village's worth on board, what the True Man/Mock Man people want with them, why even some of the supposed good guys consider them to be subhuman, or what purpose they even serve. They just are, and we're supposed to accept that the existence of such things is normal. That "Meats" are literally everywhere in the story and remain poorly explained is detrimental.
When the story finally started explaining who the good guys are, it all seems out of place. The "Director" in charge of the operation callously doesn't care about the fate of the many, many "Meats" and/or Casma, all of whom died in the operation. At the same time we're being told this organization of "Armed Librarians" is extremely beloved of the people, shown to us by people asking one of them for autographs. The incongruity cracks the foundation the world's author is trying to build upon.
By presenting the "Director" before our impression of the "Armed Librarians" organization has been set, the audience is still free to ask without hesitation "is this organization good?" The ability to ask that question freely kills any tension or interesting dynamics which could have occurred between the two. Instead of trying to understand how to two could possibly work together, much of the audience is lost to the same cynicism they display toward corporations.
This is a fairly common theme throughout the episode. Before our impressions of something can be set, the story is already moving on to the next thing we need to know without pause, pacing, or concern that some of their heroes we're supposed to like are acting like pathological monsters. Vague terms and barely described concepts are thrown at us constantly, and in the end we experience a simultaneous infodump and information void. The result of this failed world building is shaky and shallow.
Bad: There's no main character. The character we can most identify with is a supporting cast member who, by virtue of being the only character with a heart larger than the Grinch's, spends a fair amount of time expressing his belief that "Meats" are still human, that they should be saved, and expressing anger, regret and sorrow when they all end up drowning. He's also the only character that even notices Casma got blown to pieces.
We're supposed to regard the "Director" as a Major Kusanagi type main character, ala Ghost in the Shell. However, of all the characters in the story we see the least of her (outside of the ill-fated Casma) and she happens to be the most monstrously uncaring of any of the characters we meet. When directly confronted by the only caring person in the show about the deaths of all the "Meats" and the general failure of the mission, she just shrugs it off.
Then there's the subject from the opening scene. He happens to be a Meat, and somehow ends up with a piece of some witch's soul that he encountered while drowning in the ocean. This witch, for reference, poisoned entire regions and made a killing off selling the cure, but still comes off as more human and caring than 95% of the rest of the cast because she at least expresses her love of this lifeless outcast. Of course, we have no idea why a fragment of the soul of a centuries dead witch would love a random drowning stranger.
So we're not supposed to consider the only person suitable to be the main character to be important, and the people who are supposed to be main characters are either extremely confusion or for all intents and purposes inhuman. This does the story no justice.
Bad: The episode ends in a mining town. This isn't inherently bad, except the miners are mining books, peoples' souls. Why the books are in the mine in the first place and not with the "Armed Librarians" isn't clear, nor is it clear why there's a well established mining town for this reason when the only book anyone seems interested in is the soul of the previously mentioned witch.
In conclusion, the first episode of Book of Bantorra feels like someone threw a bunch of archetypes, plot elements, and tropes into a hat and just pulled them out at random. The series as a whole may well be much better, but after the first episode I have little or no reason to care about watching the rest.