When you're cycling in traffic, and really paying attention, it's a form of meditation, too. Think about it -- to be safe, you'd better be 100% in the present. You better know what the traffic around you is doing, you'd better know what the road conditions are likely to be in the next quarter mile, you better know how the traffic signals are sequenced, and you better be watching for pedestrians to boot. (Hey, "pedestrians to boot" -- get it? Never mind.) There is really no room for having your mind wander, not if you want to be safe.
There's really no room to indulge in anger or reverse road rage, either. The only time all last year when I came close to having an accident was when I was agitated when I was signaling for a lane change and a rude driver came right around me, ignoring my signal. I got all bent out of shape, and yelled at the jerk. Within a minute, and while I was still agitated, I came within a hairs-breadth of turning left into oncoming traffic. I must have had a guardian angel give me a dope-slap to pull me out of my agitation and save me. I was really shaken by this incident and by my inattentiveness caused by my not letting go of the anger.
Seeing the danger in "reverse road rage", I resolved to mend my ways. When drivers act stupid, aggressive, or (as is usually the case) heedless, I still shout at them, but then I let it drop, and be over. It's the only way to be really safe. Hanging on to your anger and agitation is just purely dangerous.
Peace, sisters and brothers.