Yeah the difference even state to state can be pretty stark.West LA and East LA only places you'll find bike riders. Veryyyyy different kinds though .
Seriously from SD, Cali right across to Tennessee may as well be a different country to LA/NY. (although upper east coast is one part i havent visited; Florida -Chitown-NY next trip)
Only place I was ever threatened was a Target carpark in the mid west for talking funny...