Riding home on a MUP, I once saw 2 guys, one on a flatbar roadie and the other on an old school roadie. The flatbar roadie was ahead, but everytime the old school roadie would yell, "On your left!", the flatbar roadie would speed up so he wouldn't get passed. This went on for about 1.5 miles because when they both passed me and I saw what was going down, I picked up the pace to trail them safely about 50' behind and watch the show. They were both a little reckless, especially the flatbar roadie.

bitpart: The CP roadies will try to pass any bike they see, not just fixies. The weekend warrior types will pass, huffing and puffing, and slow down, just to get passed again. The CAT racers will pass at 25-30 mph while holding a conversation and they'll actually hold the pace.