I've lived in the Rust Belt, the southeast, and California for big chunks of my life and you're right on about regionalisms. For language or social norms in general, all that matters is how something's taken, not what was meant by it.

If I know that some phrase is really uncommon or has different shades of meaning in a different part of the country or a different part of the world, I also know that if I use that phrase in that other place, it will get interpreted differently from what it means to me. It can be frustrating if I haven't yet picked up on the differences, but it's just the nature of communication.

I have also tried to hang on to "y'all" and "folks" since moving to the west coast. "Folks" is a harder sell though, when I use it feels more like an affectation. But that's my perception of others' perceptions. Maybe I'm pulling off "folks" without realizing it. But "y'all" has more staying power, because it's a legitimately useful term that's otherwise missing from the English language.