To date, the most dramatic would have to have been an aborted landing at HEL. (Like someone else already said, not so uncommon.) Plane was almost on the ground, and right before touchdown, the engines went back to full throttle and the nose pointed sharply back up. Caught the pax by quite a surprise. I know a go-around does not constitute any kind of emergency, but it's still a weird feeling when you're not expecting it.