Yes - I think it's nerves maybe. I tend to want to laugh out when sitting in the dentist's or doctor's waiting room - I even have to go outside sometimes because I know I'm going to start laughing. I almost laughed at a funeral once! I was so ashamed of myself and it was sheer will power and kidding on I was blowing my nose that saved the day - it was awful! The thing is I did feel really sad and there was absolutely nothing funny about it! I was also too ashamed to ask anyone else if they ever had the same experience!!