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”
Not so much breaking something but when I was maybe 5, my mom had me in summer daycamp at the Y. I got talked into pulling the fire alarm in the pool by some kids. I still remember the look on my mom’s face when she came to get me. I think this was the last straw and I was uninvited from further participation. I had earlier gotten in trouble for swimming in a creek on a day trip.