I'm pretty sure I filled out an online dating profile and listed "drivers who wave" in the "Things I Like" category. Which, at the time, meant drivers who wave to say thank you....ya know...when you let them pull in front of you or slow down so they can get in.
But I somehow forgot the even better version of drivers who wave.
In TN, and in most of any "country", drivers wave simply to say hello. There's no agenda behind it, it's simply a friendly gesture.