I like that the speedo is a little optimistic. Me being legal is more important than 3mph of inaccuracy. If the speedo was an underachiever it would be a different story. This saves me the cost of a radar detector.
I think that very characteristic helped me avoid a performance award yesterday morning. The car behind me was not so fortunate, as the Sheriff we had recently passed flipped on the lights and pulled him over, leaving me free to go on my way at a slightly reduced rate.