Happened 10-12 years ago.
I had betweem 6 or 8, and this guy had between 12 to 14.
I was playing with my friends and left my jacket i  the floor. This guy saw it and proceeded to look inside it, luckily I saw him and shouted him, a teacher also saw it, and the guy ran away.
The teacher asked me if something was missing, and yup, that guy had stolen 10 of my pokemon cards, so I told the teacher that.
The teacher knew who that guy was so after break, teacher and me went to his class, and the teacher told the guy to put all his pokemon cards in the desk, and told me to take my cards.
Apparently this guy had insanely good cards, and here is where I think I was the asshole, because since I knew the teacher wasnt going to believe a word of the other guy because he had just stolen me I took advantage of it and didnt took my cards, but instead I took his best 9 cards and my pikachu. He of course complained and told the teacher that I was taking his cards instead of mine but as I predicted, teacher didnt believe a word of what he was saying.
So AITA for taking his cards?
Reason why I bring this up 10 years later is because this weekend I was in one of those nerdy shops, and I saw one of my cards was selling for 30$, so I might have stolen something more than pokemon cards.