Mmm tough question! haha Perhaps, coincidently THE most embarassing moment took place in a forum. I told someone the name of the girl I was in love with at that time (secondary school). Unfortunately her sister was a member and told her right away! hahaha. The next day at school was really embarassing.
When I was in 7th grade I went to school (parochial school at that!) without wearing a shirt! The nun was mortified and so was I. It was so surreal. This was about the same time I Feel Fine hit #1 in the country.