My favorite: Shortly after we started we came to a red light. Lots of folks. A guy who apparently just HAD to be right at the front of the waiting cyclists jetted up and then fell right over.
Other odd scenes: People walking up the first hill. I'll bet they had a long day.
Guys with their seats super low, with their legs doing a major bow outward each pedal stroke. It hurt to watch.
Perhaps best, some guy weaving his way up the hill, using both lanes, cutting off people every few feet, explaining to his riding buddy how this made the hills easier to ride. Maybe fo rhim, but not for anyone passing him.
Over all, not a ton of bad riding. Though I can't figure out people who won't move right on busy roads when there is no need to ride 2 or 3 wide and really piss off the cars.