I'm guessing a yellowjacket is someone who doesn't care about average speed, dresses (yellow jacket/jersey) to be seen by motorists and, like some of you, really only cares about arriving at one's destination uninjured. I run max psi on whichever bike I am riding, and I go as fast as I can. It's just how I ride. Don't really care what everyone else thinks about my commuting habits, I do it because it is fun.