I think a lot of that laughter is actually nervous laughter. I think it's common when people are affected by something inside, mentally, they'll often try to make it look different on the outside. Jokes and humor often play an important role in one's ability to cope with what's really bothering them. Of course you still get the follower types who are joking and laughing simply because others are. I don't think anyone is truly laughing directly at anyone who's ill. People are strange.

Take care of yourself, man. Drink that water stuff. I heard it's good for you.