For a while there, I started really paying attention to what it took to get myself to work the quickest. I planned out my route by time, payed attention to which lanes moved at what sections, and basically had everything down to a science. I cut my commute time by an entire two-three minutes. WOW! More importantly, what I had done was made my trip a living hell. I got real aggressive. I hated when anybody got in front of me, I figured nobody knew how to merge and basically started getting pissed off at anything even slightly stupid people did around me. My trip to work had become VERY stressful.
I did this for about a year before it finally occurred to me the nut I had become. Getting pissed off at all the people cutting me off and going too slow never solved a thing. Now when it happens, I try as hard as I can to just let it go. Believe it or not, I find my commute to work (which is usually in a truck) a LOT less stressful. Yeah, it sucks when people cut me off or try to share my lane when I'm on the bike, and from time to time, you'll still see me vent, but like ironman said, there isn't much you can do about it other than learn to live with it.