banozac
I think it's cute that thing humans do when they see a boat pass and the people on the boat wave at them and they wave back. For absolutely no reason. They don't know each other they're not trying to communicate anything other than "LOOK! I am on a boat!!! Hello!!!!" "I see you!!!! On the boat!!!! Hello!!!!!!!!!!!!" in a genuine moment of wholesome human connection and excitement.
Point down with two fingers to signify "I hope you manage to keep both wheels under you, friend" ... it's very important. In the UK bikers give a little side-nod, because their free hand is on the wrong side.
When I see someone on a quad I point four fingers down :-)
Yeah we do that here when off-roading. It's not really needed on the road.