I have just stumbled across Jack Reacher, the main character in a dozen or more novels by Lee Child. A great character, principled, trained by the military years earlier, stumbling across the U.S. on his way from one unimportant place to another, getting pulled into kidnappings, terror plots, assassinations, and all sorts of goodies. Blundering his way through them.
He's entertaining to follow because, even with his training, he makes huge mistakes all the time that set his stories in motion. Someone says something to anger him; Jack Reacher pushes back and escalates the encounter up the scale. Someone kidnaps a nearby woman; Jack Reacher involves himself and gets taken along for the ride. A good guy, he wants to do the humane thing even when it's also the wrong thing for a given situation.
None of the 'mistakes' he makes are stupid ones. Good intentioned errors, misreadings of situations, intricate mistakes he might not realize for a hundred pages. In one of the later Jack Reacher novels, he interrupts what seems to him a suicide bomber on a subway train, a desperate woman who sends out all the wrong signals. Under the pressure of whatever she was doing, plus what Jack Reacher added to the situation, she kills herself in front of him. He blundered into this woman's life and he feels responsible -- which drives him through the rest of the tale.
These are the kind of stories I appreciate. A situation happens, a character does the wrong thing, and that choice powers the rest of the story. I've read too many stories lately where I can't get a grasp on why a character does the things he does. 'It's his job' is often the fallback motivation. Or worse, the character has a series of false choices (do this or die -- of course he'll do anything other than die) and he always makes the "right," or only apparent, choice. But making a mistake and trying to set it to rights: that's always a powerful motivation, in the hands of a skilled writer, for an interesting character.
As I write, I look for opportunities to let my characters make mistakes. Let them suffer through what they did wrong, especially if there was no right choice to make. Let them try to cover up what happened or fix it or make amends for something permanently altered. Let them work on their lying skills, their sleight of hand, their covering up chops.
A mistake inside a story is one place where good storytelling can come alive. Is there anything more stressful than a high-stakes choice you get wrong, that has complications, that has penalties? Conflict lives in these moments of it-really-matters failure. Let us hope for more good writers who embrace the imperfections of their characters, the ambiguity of the world, the impulse to do right even when it's all too murky to understand. A perfect character, infinitely able to read the world around him, isn't very interesting.