It's almost subconscious the way I do it, I just can't hold myself. If what I'm thinking is funny (to me, at least), no matter how cruel or stupid or degrading it might be. Not too long ago there was a conversation, and there were loads of people, it went somewhat like this. Two guys asked if they could stay over at a girl's place, and she answered she can't have them 'cause her mom's sick and she'd be getting treatment that day, at which point somebody asked if it was cancer(and cancer in my language is the same word as lobster), and I said "No, crab" with a face as serious as it gets. I felt so shitty afterwards because the laughter took more than 20 seconds to settle down. Cancer jokes rule.