I was passed by a guy on a skateboard once and it was infuriating! I couldn't understand how he was going so much faster than me and exhausted myself hauling butt to catch up with him. Turns out he had a motor on the darn thing!

BUT when I was running hills for a race I was training in, I did pass bikes because I was throwing all of myself into sprinting up hills and then walking back down them. If I kept myself at that pace for a distance, I'd be dead by now.