i did the same thing the other day, but i was walking. this guy was riding his bike on the sidewalk (common in japan) and went by me. he came to a hill and shifted about as low as he could. i was late for work so i was walking quickly, but still walking. i actually passed the biker at one point and when he noticed me he started pedaling like hell to beat me. once he got in front, he slowed down again. i would have passed him a second time if the road didn't flatten out. i laughed.