But, even stupid stuff is funnier if you can make it more elaborate with greater planning. Example from about 15 years ago:
Monday, employee walks in to work, small cup of water lands on his head.
Tuesday, same employee walks in, yet again, the perfect length of string and perfect positioning result in slight dampness - direct hit, but just a small amount of water.
Wednesday, the employee had the day off.
Thursday, employee walks in, small amount of water again.
Friday, employee gets to door, kicks door open spilling small amount of water onto floor. Employee: "Yeah! Who's the man. Who's the man now! You can't fool me any more with your stupid pranks. Yeah, that's what I thought. I'm the man now..." and continued pointing at me talking up a storm as he walked by and went into the office backwards, still talking crap. He didn't see the 2nd string. He probably would have had he been facing forward. 5 gallon bucket of water, about 2/3 full dumps on him as he enters the office.
The entire week of little cups was just a setup for Friday.