What childhood prank did you play that seemed pretty tame and harmless but on reflection, could have had serious consequences for the pranked person?

Posted by BarryFairbrother@reddit | AskUK | View on Reddit | 342 comments

I used to live near a music college. Often in the evenings the students would practise. The back of the building had a ground floor consisting of practice rooms with floor-to-ceiling windows looking out onto empty fields, absolutely pitch black outside with no way to see outside if you had the light on inside. A friend and I would go around the back and bang on the windows while people were mid-flow, they would jump so much and often quite dramatically and screaming, we found it absolutely hilarious. These were highly gifted musicians playing really advanced stuff, and also preparing for important exams. We were dying of laughter at the time (we were 14), but I’d be so angry if that was me and I do regret it, especially as I’m now a keen amateur musician myself.