Just one look at 'America's funniest home videos' reminds us that certain people prank or pull gags on people all the time. It just so happens that it is popular to record that gag for others to see. They usually pick someone serious minded (or not!) to make something go wrong on them. The fun comes in seeing the protagonist's reaction. Our fun comes not only in seeing the protagonist reaction but also in seeing what happens to the antagonist. Many shows make use of the gag. 'I Love Lucy' comes to mind.
The antagonists have gotten smart though: If they can pull the gag and get it recorded and be there to see the reaction without the protagonist knowing it, that is also very funny to me.
This film opened the door to many of the possibilities. I'm thinking of someone I could prank right now...