Some times I laugh at things I really shouldn't, but just can't help it.
For example, walking through town recently I saw a father and son ahead of me. The son, aged around 10, was 'leap-frogging' over some metal bollards in the street. He missed his aim slightly and ended up hitting his delicate regions on the bollard. That wasn't the part that really killed me though; as soon as the boy straightened up again his father gave him a clip round the ear for being so stupid. It was one of those you have to be there moments, but I was in tears of laughter. I couldn't help but think that the kid had probably learned his lesson without the reinforcement from dad.
Have you ever laughed at something that really you shouldn't have but just couldn't stop youself?