"I know there's all this talk about my charisma deficit and I have to admit that I'm not a wild, in-your-face actor. It's not my nature to be flashy or extroverted, and that's why I see it a great challenge to me as an actor to be able to play against type and shake up people's perceptions of me." -- Tobey Maguire
Stupidity is not the same as personality. That is to say, even a stupid action has to fit within the character's personality. That's not always an easy thing to do, especially when we need a character to act in a way that the audience won't expect.
This is where the Enneagram can be very useful as a typing system for your characters.
* * *
And this is where you need to click the link to Indie Writers Monthly. Go find out about personalities, maybe even your own. Do you know what number you are?