Oh, I have a few. I tried to cover a V4 with crayola magic clay when I was in elementary school, because I wanted to see how a new design of mine would look (spoiler alert--BAD). I let my little neighbor borrow my first tamagotchi ever and she broke it... I was really sad but after, like, 7 years, I'm getting a new one (version 2 in pink) in the mail any day now! I also clipped my six tamagotchis to my backpack, left my backpack in the hall, and came back... to 2 tamagotchis.
I also used to (as in, from age 8 to a few months ago) starve my boy tamagotchis to death because I wanted a cute girl adult. I regret doing that sooo much now! D: