Once, we were doing a physics test at school and we where divided in two groups based upon the first letters of our surnames - first half of the alphabet was in the group A, and the second in the group B. I had this friend whose surname, as I would later discover, I didn't get quite right. His actual surname was kinda unusual for me ( cuz I never heard it before ) and it started with letter T , but I somehow changed it to D in my mind which made it sound really funny ( something to do with masturbation - guess the rough translation in English would be something like - Jerkoffson ) So when we started going into our groups I saw him going into same one as me ( group B ) and asked him why was he joining the wrong group. He replayed he wasn't, said his surname started with T and asked me what I thought his surname was. I said something like I can't remember or nvm but I could see in his eyes he knew what I was thinking.