As a sophomore in high school I had a friend (not much a friend really, he was kind of a d^ck) who came from lots of money- first car was a Vette. C4. He went on vacation and myself and another friend knew where the spare key to his house was.
We borrowed the car.... and the house... for a few days of partying and what have you. Drove it all around town, everyone saw us. Everyone knew it was Jake's car.
When he got back and found out... well... we were no longer friends.