I hit a pedestrian once. I was young, 10, maybe 12? Riding along, chatting with a friend. I looked forward, and there was a little old man standing on the side of the road. I look over at my friend, and keep chatting. I look forward again, and the man is TWO FEET IN FRONT OF MY WHEEL. There was nowhere to go; I braked as hard as I could, but I still knocked him over. To this day, I'm still not sure how neither I nor my friend noticed he was right in front of me until I was right on top of him.
I felt just about as crappy as you can imagine.
Luckily, he was ok. A bit shaken up (I was too), but ok.
I can't imagine hitting someone and just taking off. . .