I wave and dont care at all if they wave back or not. I dont wave when I am holding on for safety reasons. I speak when I pass someone. I guess a lot of times if you are on a bike several lanes away I might not even think about you, many bumps, pedestirans, dogs and goodness knows what else we have to watch. I think most everyone is ok, and try to treat them as such on a daily basis. Oh yea, I have a jeep and every one in a jeep waves at me. sometimes I forget and will notice someone waved at me just as they pass. I wonder if they think I am a jerk cause I dont wave back?