Obliviousity
When you're so out of touch with reality that you think everything is normal, even when it's clearly not.
You're at a friend's house, and they're all screaming about a video game, but you just say, 'That's normal, right?' and keep eating ice cream.
Your friend texts you, 'Why did you miss my birthday?' and you say, 'I thought it was next month!' like that’s the most reasonable answer.
You're in a group project, and everyone is arguing about something you didn't know was a problem, but you say, 'I’m just here for the snacks!' like that's a valid reason.