Worse thing I've ever done was when I was 18 I got drunk on a night out at college and lost my expensive digital camera. I told my parents I got mugged walking home so they'd feel sympathetic and buy me a new one. They did.
. Unfortunately they called a friend
(I was in England at college and they were in Ireland) and got the friend to come round to make me to go to station and file a police report. By that point I didn't want to go back and tell them I lied so I went. I felt so guilty and thought I would get caught.