I seldomly get a nod or a wave out of a roadie on the bike path(s). I used to think it was because I rode my mtn. bike on the path. I even started wearing a one piece spandex bib. Still no waves or slight nods but, I was aerodynamic. So I finally purchased a road bike last fall in search of the mysterious head nod and....nothing. Roadies waving or giving a 'wa sup' head nod is much like sasquatch or the loch ness monster, I will believe it when I see it.
Don't get mad don't get angry thats just the way it is.