People who run stop signs.

[Jimbo]

My family frequently expresses displeasure driving with me because if I see someone distracted on a cell phone while driving I may yell as loud as I can, "Get off the bleeping, expletive, expletive phone and just drive," which in the warmer months they will hear me.
But on the topic of stop signs or stop lights I am frequently frustrated by how many people feel that the "right on red" concept doesn't mean they need to make a complete stop and observe before completing the turn. I go thru two on the way to work and if I make a complete stop I'm apt to have some idiot behind me lean on the horn. When that happens, I feel the need to be concerned about the safety of my fellow drivers and I remain stopped until the light turns green (and hopefully I have really pi$$ed horatio hornblower off.
There's so many Stupid Driver Tricks, Letterman could make it a weekly segment.