I work in I.T. so I’d pull technology pranks.

• Cause a lag spike when you’re about to frag someone
• Make your download fail 90% of the way through
• Move your files from one place to another so you can’t find them
• Make your phone battery run out of charge before noon

And little stuff like

• Make nothing happen when you click the first time
• Make the window scroll slightly past the spot you want to go to
• Bring a different window into focus right as you’re about to type something