I'm the same way, almost nothing bothers, but every now and then something big happens and i snap. it's never little things, just big things. I really don't think anyone could believe i could be that mean unless they have seen it. Recently, if it's even possible in the situation, I try to think of some smart ass comment to make whoever feel like a complete idiot. I have a friend who does this often and i think it's hilarious, so i just try to make a joke out of it.