First one has never happened to me, but the second happened because my brother's annoying friend was chasing me around the neighborhood. But if someone like Tom Felton (or that special someone I am not naming) was in front of me, I would definetly run faster to catch up with them, or go past them to make them think I'm more athletic, I just love beating guys at sports. And about the Tom Felton thing... I have a ridiculous schoolgirl crush on Draco Malfoy.
