People who pull pranks, make jokes, and do things that annoy other people — but aren't really awful — are good at mischief.
Mischief is a word for things that are a little bad or reckless but ultimately harmless. Hitting someone with a spitball is mischief. Hitting them with a rock is dangerous and therefore much worse than mischief. Making mischief can be fun, as long as it doesn't get out of hand. People who do a lot of mischief are called "mischievous."