often times a motorist will see a cyclist, but they simply do not accurately gauge a cyclist's speed.
often times, people see a bicyclist and they think they are going 10mph.

conversely, I'm especially annoyed when I'm climbing a steep hill, pedaling out of the saddle, when a motorist waits at an intersection for me to pass, as if.... what?
because they see me out of the saddle, it looks like I'm sprinting or something... never mind the 8% gradient, which most people do not know how much effort it takes to pedal at 10mph for even 1/4 mile.

downhill descent on a 4% gradient, most people hardly notice the descent, much less are cognizant of a bicyclist traveling at 25mph, the are apt to pull out in front of you. they simply have a hard time judging time and distance.


my pet peeve are city buses. of course bus stops are located near corners. corners are where intersections are located. often times, a bus passes by hard on the gas, only to pull over in front of you, for a bus stop. Luckily I don't live in an area where I have to fight bus traffic.