I think it's a defense mechanism. Your brain chooses to make fun of things because if you took them seriously you would get crazy from feeling so much.

It happens to me too. I am usually hypersensitive but on the other hand I have periods or certain cases when I don't feel absolutely anything. I know rationally when I should act like I'm being touched and express sympathy but I don't really feel it. At first I was shocked by this lack of feeling but I came to understand it's actually a proof of being too sensitive.