Not talking about the teen stuff, but really childish things..
I remember stealing a Milky Way chocolate bar- I couldn't have been older than 6 at the time. Mum was grocery shopping and I just stuck it in my pocket!
Then, around the same age, I snuck out of the court on my 3 wheeler bike and rode to the milk bar around the block to buy a packet of "Neighbours" trading cards. Remember those? lol... They came with a little piece of pink gum that was terrible tasting and as hard as a bullet. Yum. Anyway, I got home and mum questioned me about where I'd been (she was in hysterics!) and I lied- told her I'd found the cards in the vacant paddock lot at the end of the court- but she smelled the cards and the bubblegum smelled too fresh so she knew that I was lying! lol... busted.
But, the worst thing I've ever done was, by far, putting a pin on my teacher's chair in grade 4. OMG... looking back now, how terrible is that!?! But I remember her sitting on her chair and she must have (luckily) knocked the pin over as she sat, because she was fine. It was probably a prank that I'd read in a book or something, but thinking about it now, as an adult, I'm horrified that I had the audacity to try it.. that I wanted my teacher to be pricked by a pin..!