Every now and again, someone will try to defend a fictional character’s incoherent actions by saying that it’s because of realism and that real people don’t always behave rationally. While it’s true that real people don’t always behave rationally, they still have some reason for doing things. It might not be a good reason, but there is a reason, and it is the storyteller’s job to explain that reason. Characters can make dumb moves for no better reason than “it was the middle of a gunfight and they didn’t have time to think of something better” or “they’re unreasonably suspicious and think everyone is lying to them, so they don’t trust their partner even despite all the times their partner has come through for them,” or “they really want treasure and are willing to take absolutely suicidal risks to get some.”
Each of these three examples leads to predictably sub-optimal behavior. Someone who tends to lose their head in a fight will frequently make dumb mistakes when fists and/or bullets are flying, someone who’s unreasonably suspicious will be unreasonably suspicious of everyone, someone who’s suicidally greedy will be suicidally greedy for all treasure. And if these motives are set up in advance, no one but idiot pedants will try to nitpick their motives as not making sense.
Even actually diagnosably crazy people have reasons for taking non-optimal actions, even if that reason is “because I’m certain this Kwik-Mart manager is a pawn of the alien conspiracy spying on me.” If there really were an alien conspiracy spying on a plucky investigator through alien spies wearing Kwik-Mart manager skinsuits, it would make sense to avoid that Kwik-Mart’s whole block and maybe sneak there in the middle of the night and burn the whole place down. That’s an insane delusion, but the actions taken as a result of that insane delusion make sense.
The vague, ambiguous statement that “they’re crazy” or “people aren’t always rational” does not excuse characters behaving in a manner that’s contrary to their own goals without explanation. In order for irrational behavior to be used to explain character action, that behavior must emerge from character motivation, because everything used to explain character action must emerge from character motivation.
As one example, when people ask why the protagonists of A Quiet Place don’t just move to the waterfall, saying “people aren’t rational!” is not an explanation. Most people arrive at the “why not move to the waterfall” solution within weeks of watching that movie (if not hours), while the protagonists have had two years and a much stronger incentive to try and find a way to get safe from the monsters. The entire movie revolves around how people have developed methods to hide from these monsters, it is the driving conflict and motivation behind everything that every character does (I mean, except the one guy who gave up and screamed, but that reaction being unusual was the whole point of that scene), and this obvious solution has gone completely ignored. Real people would’ve figured that out and immediately pulled up stakes to get where it’s safe, because that’s what people facing life-threatening danger do. When the Abbotts fail to do that, it makes them less believable as characters and thus makes it harder to care about them. For some people, this problem doesn’t occur to them until after they’ve watched the movie once, in which case it will still impact repeat viewings. For others, it hits them within the space of the waterfall scene and damages the movie as it happens. That’s not a trivial nitpick. It’s a flaw. Characters need coherent motivations and their actions need to flow from those motivations. Just saying “sometimes people are irrational!” does not immediately excuse characters behaving contrary to their goals.