I actually do have a running confrontation story. A year ago, while in Philadelphia for the Penn Relays, a few friends and I went for a run along the Shuylkill river, which is right near UPenn and has a nice path along it. As we're a couple miles in, we go by a young boy and girl, probably 10 or so, just standing around/walking.
Then, on the way back, the boy (in jeans and carrying a foldout paper fan, for whatever reason) decides to come run with us, telling us about how fast he is. So we're saying, "Oh, we got a runner," "future cross country star," etc. I believe there may have been talk about challenging us to a race as well -- hazy memory.
But then after about 30 seconds (he's running next me, starting to get winded), he gives me a sly look, then punches me in the shoulder, turns around and sprints the other way. We continued on laughing, and I yelled back something like "Just wait till next year! Penn Relays '09!" Needless to say, he was a no-show this year.
Once on a trail at school, I was running along, passing two guys on an uphill. At least one must have been Jamaican, because he glanced over as I went by and said in a awesome accent, "You make it look so easy, mon." That brightened my day.
Best "Run, Forrest, Run" comment: Two years ago, our whole team was doing an easy run right through the middle of downtown Eugene the day before a meet, probably not a quarter mile from Hayward Field. Tracktown, USA, right? Well, we're running along when a beard in a pickup going by leans out the window and delivers that classic line in a classic drawl, before driving off.
You may be faster than me,
You may be stronger than me,
You may be smarter than me,
But can you beat me?