This annoys me SO MUCH! I mean, you have to start over the problem and everything! This happens to me all the freaking time!^^ I don't even do the problem again. I just pick the closest answer to mine.
Especially this happens after you jump waves at the beach. At night you feel waves and when there's a a big wave you jump<< I scream and then pretend nothing happened when someone comes to check on me xD