Thank you! If I'm unhinged, at least I'm happy unhinged, and giving back a little kindness.
No, I don't wave to 'everyone', but I will wave to thank drivers who stop so that I can cross a road, or people who are vaguely familiar. I will also chat briefly to the drug addicts and alcoholics at the bottom of the road which is in fact an insurance. They are way less likely to attack or rob me if they know who I am. I help people out, and even yesterday stepped into the middle of the road and put my hand up, stopping all the traffic, so that a disabled man (now he looked unhinged) could cross the road.
I believe that connecting with people not only makes the world worth living in but is what we're here for.
As for the OPs question (and I'm so sorry to have digressed), yes, it was rude, but you obviously feel uncomfortable about it or you wouldn't have asked for people's opinions. Perhaps next time something like this happens you could at least acknowledge it but also just say that you're a bit busy, with a smile, if you don't wish to interact. I know that at times it can be annoying.
So back to unhinged. I actually don't care if that's how people perceive me. Their loss!