in colorado i notice that people are friendly for the most part. cyclists can be overly nice, but the majority of them ignore me, except to give me a heart attack yelling out "on your left." i always wave at other runners, and don't get too high a response rate. but if you say "hi, good morning" you'll get some kind of grunt back. i usually only wave, way to out of breath for talking.
in michigan, there weren't that many runners out, and almost no cyclists at all. they were generally friendly.
in los angelos, i noticed that people don't give thank you waves while driving at all. we let someone in, no thank you wave. then someone let us in, we gave them a wave, they looked at us like we were insane.