I agree that the first weeks of good weather bring out more riders than the last few weeks of good weather in the fall. And I agree that with the increase in numbers of riders, there is a decrease in politeness. Beyond that I dunno.

Sometimes I do suspect the more gear-oriented riders seem to judge other riders by their gear, and if it doesn't measure up to a certain standard, the rider I isn't worthy. The guys in lycra don't often wave at me, I think because I don't dress like them. But it's hard to tell what goes through their minds.