I've had this a few times as well. Once or twice I reacted horribly due to being exhausted. Do not aggrivate me when I am tired! Why does this always happen later in the week after many miles?

All in all this occurs rarely. I either do not respond or give the one finger salute but every so often I engage in a debate. Once in a while, when feeling particularly froggy, I respond with a kiss or a salute.

The best method would be to let it go but I do not always take my own advice.