Speed of Driving
It's a little stressful when you're driving exactly the speed limit (of course, I would never go beyond the posted speed limit) and someone zooms by you at 10, 15, or sometimes 20+ miles per hour. As a bonus, these people will usually weave through traffic too. What's so important that you'd risk your life, and several other peoples', to save some time? Maybe, man's gotta poo. Who knows? But something I do think about, is how much time are they actually saving, assuming they don't get into a crash or stopped by the police?