When I'm on the main roads, people sometimes shout at me from their cars. It's never been anything but positive, but at first it made me feel exposed. Or like this one time when I was cleaning out a storm drain, a dude stopped his car in the middle of the street and thanked me profusely for doing it. It took a while to figure out to how to respond when stuff like that happens.
Now, I usually just clack the grabber up in the air to acknowledge them 😎