Seems like old people like to ride their brakes and you NEVER know when they are really gonna use 'em! Brake lights are always blinking on and off. Really gets nutz when they actually use a turn signal!
Heavy wind and tree branches.
Rednecks, tow chains and towed vehicles.
Farm equipment on skinny roads. Hay bales improperly secured (square, round no difference).
Tailgaters, cell phome talkers/texters, loads of kids in anything.
Emergency equipment enroute behind on skinny roads (you gotta speed up until you can get off or they can pass).
County or state service crews on skinny roads at 3:30 pm with you following (gotta go slow to run out the clock).
Fresh oil on road prior to pea gravel, chip n' seal roads with Maxxis tires, steel grates on bridge transitions, trolly tracks (San Francisco), boards, pipe, pallets or pieces thereof anywhere.
People who continually creep forward at stoplights (does that really make the light turn green faster?).
People who do their stopping in the last 20 feet with you riding towards the intersection. People who do NOT stop when required!
Karl