I laugh at inappropriate times... Sometimes it's just me laughing and I know I should stop but I just can't.
Like on the rare occasions when I go to church. I get so bored, everything seems funny. So I laugh. And it's just me laughing. Nobody else in the entire congregation is laughing except me.
Or, God help me, at a funeral. If I don't know the person, I get so bored, and everything seems funny. So I laugh and my mom smacks me upside the head.
I laugh at things I shouldn't, too. Like when somebody falls. I'm sorry, my first response is to laugh THEN ask, "Are you okay???"