Reddit top voted comments...
Ask questions during movies while said questions are being answered by the movie, so the person you're watching it with has to rewind. Endless loop
Unplug peoples cell phones in the early of the night after they have fallen asleep.
I take a really long time taking pictures of famous paintings...with an iPad held above head height.
Press every button I come across.
I would purchase everything in pennies
Walk really slow on a narrow sidewalk