Has anyone complaining about the alleged rudeness of Bostonians and other people from the Northeast considered that, from the other side, THEY are the rude ones for attempting to force a meaningless, empty interaction with a stranger who is minding their own business? 'Cause that's how Southern friendliness has been read by more than a few Northerners - as aggravating, insincere busy-bodying. Which is rude. That's just not how we interact up here. It's confusing and irritating. We're really nice people, I swear - once we've been introduced. C'mon, cultures are different. Try not to take it personally.
As for the alleged parochialism of people in Boston, I find it hard to believe that it's that much different from a lot of other places. How would most residents of a Southern city take to my Northeast-bred manners? Would they let it go, or would they complain about that rude, elitist Yankee who is too good for Southern friendliness? C'mon.
Oh, bikes? Um, sometimes I wave. Sometimes I'm tired and tuned out, or riding hard, or just plain don't really feel like interacting with other people. Rude Yankee that I am, I don't see anything wrong with wanting time to myself without pulling myself out of my personal reverie to validate passing strangers. Sometimes I ride for the solitude. That's not elitist, that's being an emotionally healthy human being.