There are a few different types of cyclists. The first type is the Sidewalk Riders. They fail to recognise that they are in fact vehicles, and belong on the road. This brand of cyclists also almost never have bells on their bikes, and never bother to get your attention when they pedal up behind you. I've been run over by 4 such people. It's like they think they're pedestrians like everyone else, and they don't even consider the fact that running over people, even on bikes, hurts. Usually, they don't even stop to help you back up, or to apologise for being idiots.
The next form of irresponsible cyclists are the Wrong Way Cyclists. These people do ride on the road, but they seem to think they are exempt from street signs informing everyone that the street is one way, and they also fail to give warning signs about which way they're going to turn at street corners. Guys... you're vehicles. You do have to obey the rules of the road. The thing I love best about these bikers is that they get really annoyed when cars hit them. Of course cars hit you! You're not where you're supposed to be or doing what the rules tell you to! It's ridiculous how cars get blamed, when really how can they be expected to read the mind of bikers who refuse to accept that rules apply to them?
Then we have Invisible Cyclists. They ride on the road at night, and wear black, and don't light their bike up at all. Chances are they don't have a helmet on, either. Sure they're obeying the rules... but they get hit anyway because drivers just can't see them. Of course, they then blame the drivers for not having better eyesight. How does this make sense? I don't know. You tell me.
Of course, you do find the odd cyclist who obeys the rules. They stay on the roads, wear bright colours at night, have bells, signal their turns, and only go the right direction on one-way streets. I commend these cyclists. However, there are so few of them that I will continue to cringe in terror every time I see a bicycle headed my way.