Having lived in the NE and the South, there is a big difference in behavior. And, what "Northerners" see as "normal", Southerners would consider rude and snobby. Part of it is what you are used to. I think generally Southerners are much more outgoing and congenial to strangers, and will readily treat folks "like family". Something simple like smiling and waving, with a verbal greeting ('morning, good afternoon, etc), is a given, whereas you are not going to see that much in the NE, where "minding one's own business" extends beyond the home. There was a big enough difference for me to remark to myself, after a few months in SC, that the phrase "Southern hospitality", was quite true.
Also, re driving in south vs. north. There is a difference between Boston and the regions around Boston. I used to drive into Boston on a regular basis from a neighboring state, and I would find the drivers becoming crazier and crazier the closer one got to route 128 and Boston in general.
Then I taught in South Carolina for a while. Things are definitely slower and more mellow in the south. And if there you wanted to make a left turn, with a long line of traffic approaching you and no lights or break in sight, the southerners would actually stop and let you go. That is unheard of in the north. People from Massachusetts just pull out into the middle of the road so that the oncoming traffic has to stop.