Moths are the one harmless thing I have an irrational fear of. A couple of times when I was very young a biggish moth got into my room a terrorized me (I'm guessing because of the way the light played off of my clothes).

I don't go out of my way to exterminate them, but if one follows me inside and resists my first couple of attempts to catch and release it, I'm going to smash the hell out of it.

I'm mostly over the visceral fear at this point, but if a big bastard is flying around a porch light I'm not sticking around.

Edit to add: I would probably smack a butterfly out of the air if it got in my face the way moths do. Equal opportunity irrationality.