Valet drivers. Only encountered in very specific places, and usually for short durations. I worry about them more than I do cabbies. Tip is dependent on how fast the car/suv comes back. Usually young, inexperienced drivers to boot. These are the ones that I worry about the most.

What is your most feared driver 'class'?

Single occupant vehicle commuters are the worst usually very cranky. They seem like they have this God given right to own the road. I say this from a cycle/car perspective. I don't have much experience with valet drivers

I ride by the 3 direction entrance to the parking lot of one of the richest public schools in my area, that has the highest level of students driving to school. Many have sports cars and jacked up trucks and are out to prove how 'special' they are. I get right hooked, honked, tires squealing, engines rev'd, yelled at, etc. just about every morning when I pass the line of cars waiting to fill the parking lot

Al

I'd never let a valet near my car.

However, worst driver scenario for me has been young male with car load of friends all on testosterone overload

1) Selfish people who do whatever they want cuz they think the law doesn't apply to them
2) Clueless parents picking up kids at school
3) Cellphone users (and that includes the hands-free headsets)
4) People who drive way over or way under the speed limit

taxi drivers, but it's often due to the "ohh wait pull over here, NOW!" passengers backseat drivin, not knowin where the hell they are.

..If I had a dollar for all the times they've cut me off and pulled right in front of me to let off passenger or turn, grumble grumble

i agree with that. thankfully they are easily avoided, as they operate in a small area. but yes, they are freaking dangerous sometimes!

i still have to go with cabbies though, and at a close second - vehicles with loud sound systems. they seem to feature younger more agressive drivers.

Old people in Crown Victorias. I don't know if it's senility or hatred, but I sure wish they'd act all wise and kind like they do in stories...

...NOW WITH 30% MORE THUG!

1. Senior citizens in their big Caddys
2. Testosterone filled younger males with something to prove to their friends.
3. People who are looking for parking on the street and all of a sudden stop because they just saw a car that may be pulling out.
4. Cellphone users - hands free or with hands - doesn't matter

Be careful about profiling young drivers that have systems in their car. I have a nice system in my car, but I am also one of the safest and most polite drivers you will find. I can actually maneuver my car while on the phone too. Seems crazy, huh. I just get mad when I see people that can't talk and drive at the same time...it is the same as having the person sitting next to you!

I'll go ahead and second (third?) the "young males with too much testosterone."

I have a good, non-bike, valet story. I live in Pasadena a few blocks from where J-Lo opened her restaraunt. For the grand opening, all of the Hollywood stars were coming so my wife and I walked down to have a look. The valets put on quite a show. One stalled a Lamborghini six times. You could smell the clutch burning by the time he got it to move. Kobi pulled up in his Ferrari. The valet got in. The reverse lights came on. He shot backwards four or five feet and stalled it. He was trying to go forward. The the reverse lights came on again, then off, on, off, on, off, on, off. Then he reved it up to about 5000 rpms and let the clutch out over the next 20 seconds. Ahhh, that smell again. Kobi had turned around and was heading back by this time. (The guy has to work for a whole hour to buy a car like that.) Another Ferrari came in and the guy ground the gears twice. Then I think he discovered what that pedal on the left did. Jay Leno (a car guy) took one look at these clowns and parked his own car. This went on for about an hour. What a show.