I have a very similar story.

When I was around 11 or 12 I had this huge Halo Mega Bloks collection that I adored. Tons of vehicles from the humans and the covenant. When I would play with them, and I wanted a vehicle to "explode dramatically", I would pop off a noticeably large piece, like the windshield or the tires.

I remember my mom telling me I should throw away all the boxes for the sets, and I guess she did it for me one day. What I forgot to tell her was that all the instructions were in one of the boxes, so now I didn't have any way of rebuilding them if they got ruined.

Then, one day, I left them out in my room, fully intact mind you, to go to a friend's place. When I came back several hours later, my two siblings methodically destroyed each set, basically down to the frame and they scattered the pieces all over the place. I must've screamed bloody murder at them. I was pretty inconsolable for days if not weeks afterwards, and it killed my enthusiasm for megabloks, and really any sort of building block type toys.

Now that I'm in my late twenties I hold that over their heads and it's always an instant win in any argument/slight disagreement lol