Worst is when you see a bike cop doing any/all of these things.

What makes my blood boil is that by ignoring the laws, these idiots make the behavior of bikers completely unpredictable to drivers, and thereby make biking less safe for everyone. I obey the laws (grudgingly some times -- I HATE not passing cars waiting for red lights), but I hope that my actions are not then completely unanticipated by the cars on the road. However, unless the driver has seen me on my route, and remembers me (lord knows the driver of the Ford GTO that revs past me most days recognizes me), they don't know what to expect from me.

And what about people wearing unclipped helmets? Sooo tempting to flip it off their skulls as they zip past on the sidewalk!

SJ