Mine was our CRT TV. I would rapidly push the power button on and off because I thought the picture coming and going looked cool but eventually it fell inside of the TV. I think I later stuck a magnet on the TV.
Not looking for Reddit answers like “My parent’s marriage”
My grandparent’s desktop computer. I didn’t break the hardware, but i set the default font size in windows 98 to some ludicrously high value. That made it so large the OS became unusable and the dialog to change it back was also unusable. Probably a quick terminal command would have fixed it within a couple seconds but I wasn’t old enough to understand that and my parents weren’t very tech-savvy.