I try to speed intelligently. Despite what the people here who like to point out that they are good at simple division will tell you, t = d/r is not always a reliable formula for computing your travel time. A lot of drivers seem to be determined to stop at every light, and getting just a bit ahead of them can result in significant time savings.
However, in my case this enlightened approach applies only when I'm driving my car... the route home includes a stretch of twisty, hilly roadway with no cross streets, and when I'm on the Kawasaki, the urge to crank the throttle is often more than I can resist. I've passed cops going the other way when I know that I was doing at least 20 over, and none of them have turned around yet... I usually decide that I'm going to have to go slower in the future, but my resolve has yet to last until the next time.