>>/307/
> I was once sent home for biting another kid on the arm
Well sounds like you were pretty antisocial back then. I don't have any fond memories I had a pretty bland childhood with nothing of much consequence. 

 >>/307/
> There's something about bad or embarassing things that gets forever burned into our brain.
Maybe it's a response in order to make sure you don't repeat the same mistake over and over again. That makes most logical sense to me.