Do you wave to the other cyclists ??
Do you nod ?? or do you just keep going, eyes straight ahead ??
I usually just nod, but I find the situation kinda awkward sometimes.
The real serious looking full-gear "pro-team" types usually don't nod or wave back,
so I don't wave at them. I do at anyone smiling, or making eye contact.
Usually the casualy dressed cyclist seem the most happy.
Just an observation.