Very interesting and fun to read thread.

On my rural commute where other cyclists are quite rare I will wave or say hi. But yesterday I went for a 130 kms ride on the bike trail with some friends and we didn't wave anybody because you can all guess what people were doing on the bike trail...

It make me think of something similar, there's a constructiuon zone on my commute and for the last 5-6 weeks I chat every morning with the flag lady while we wait for our turn to pass thru the construction zone. We're now friends, I happen to know her parents and my father was her 6th grade teacher 35 years ago... this never happen in a car...