What do you do when you see close friends, acquaintances and colleagues, or when you meet complete strangers for business meetings? You greet them. It’s just an instinct. How you greet people, however ...

My friend K. recently made a new female friend. "She's awesome," he says. "There's just one thing...She kisses people on the lips when she says hello. Is that weird?" Uh, kind of. I'm curious: How do ...