Whats the worst thing you have ever done too a person that liked you?

When i was young a stupid i dated this girl.she was a very nice girl.I was an idiot.Anyways I planned with my mates.that when im in her house alone with her(she was well off),I will leave the back door unlocked.We will end up in her room and id blast the music so she doesnt hear anything.After an hr or so in the room,we come out and my mates had taken the tv/stereo/dvd,anything of value.I acted shocked that her house got burgled while we were in the room.At first she was freaking out but later calmed down and said dnt worry about it coz her parents were insured etc.Felt pretty guilty after that and ended relationship soon after.many yrs later i still havnt forgiven myself for what i had done.