I'm reminded of a time when I was out alone on my road bike, wearing my cycling gear, and I passed someone going the other direction. He was in dirty street clothes riding a battered standard. I waved and nodded as I went by. But he'd already made up his mind that I wasn't going to, to the extent that he didn't even look for my wave before he sarcastically sneered Good Morning at my back. Now, who was the snob there?

Ride your own bike. Wave if you want. Don't wave if you don't want to. Life's too short to spend it judging other people.