There are countless small differences between where I grew up (Michigan) and where I now live (Philadelphia) that I had to learn in order to fit in. I no longer say "downtown." Instead, it's "Center City." I don't go "to the beach." I go "down the shore." And, of course, moving here meant that I had to stop rooting for my beloved Tigers. (Go Phillies!)
Smiling is good for you -- both physically and mentally. In fact, there are a slew of scientific studies that prove the physical and psychological effects of smiling. And I'm not talking about fake smiles, but honest-to-goodness smiles that reach your eyes. They not only affect you, but also have an impact on others around you.