Pet peeve: the whole chair thing after the first big snow to preserve your parking spot. I know it's slightly off-topic, but actually it's somewhat related to public transit, since you don't need to do it if you don't have a car in the first place. I have never seen this anywhere else I've lived, by the way. I know it bugs the mayor, too, though I don't know exactly why. There are aesthetic considerations, of course, but the custom really cuts to the core of what's so very unappealing about Boston's bad attitude, in general, aside from looking trashy.
What bugs me, personally, is not so much that people do it the day of a snow storn, after they've labored to dig out their vehicle, thus clearing a spot, but that even well after the entire street is cleared they continue to claim that spot. This shows their true motives and mentality. They just feel entitled to a spot, period. And a little snow gives them a perfect excuse to claim it in perpetuity.
When a friend of mine dropped me off a couple days after the whole street had been cleared, I was going to invite him up, but it was around five, and the free spots on the street were all "claimed," with a chair or a pylon or a wastepaper basket to mark them, and he said, the thing is they'll key my car if I take "their" spot.
And that's how it is here all winter long. People just lying in wait for an excuse to attack. Yes, that chair looks inviting, but it's not for sitting. It's really an invitation to rumble!