So I'm driving home just now, it's 8 pm and completely dark. At a busy 4-way stop, it's my turn, so I start to go, only to have some schmo' on a mountain bike riding up the cross street from the right blow through the stop sign and turn left in front of me. OK, he had his little light in the front, but even that wasn't visible until he went through the stop sign, since (I realized later) he had passed a couple of cars on the right side coming up to the stop.

And of course, most drivers would see that and say, "Damn bike riders!", making those drivers less likely to be willing to share the road.

I'm just glad I didn't have to clean him off the grill of my wife's Sequoia that I was driving...