Eh, it works fine enough in the Boston area. The key is to be able to read people's response quickly. You make a small comment or witticism, and they'll either give you a non-committal remark back or they'll literally light up and begin conversing with you. If you continue on when they haven't reacted positively, that's when you're perceived as annoying or weird.

I'm from the south and visited Boston earlier this year and I feel like people really overdo the whole "southerners are overly nice and in your business" and "northerners are cold, uninterested and busy". People we're equally nice in both places and we had some nice, brief conversations with strangers. A friend of mine who I was with is German and he seemed to think people were exceedingly friendly

Exactly my experience. The key is to start the conversation in a way that also allows the other person to exit and save face. If they don't feel trapped it's much lower stakes for everyone involved.