Walking into people who stand in the way or walk extremely slow on purpose.
Working in a 13 story building, I would often press every button on my way out on the ground floor. Only did this when alone, and no one was entering on the ground floor. So some poor guy would get on at floor 2 or 3 and have to stop at every floor on the way up.
Last time I did this, stepped out of the elevator and some guy rounded the corner in a hurry, saw the doors closing, and bolted to get into the elevator. All I heard from behind me was OH COME ON JESUS CHRIST. He knew.
When someone I don’t like is right I make sure to say, “Are you sure about that”. A good amount of the time they end up changing their statemnt and become incorrect.