A friend of mine has a "no hug" rule. It's interesting watching him trying to enforce it, now that passionate embraces have become a standard greeting between people who don't even like each other that much.
Sure, there are situations where brisk handshakes still suffice – eg, meetings with your mortgage broker – but it's only a matter of time until discussions about tracker rates and indemnity guarantees will preceded by tender squeezes to the upper body. My friend, however, will go down fighting to stop this trend, even if he perishes under the weight of eight or more people trying to give him a hug simultaneously.
If someone approaches him with arms open wide, he puts his hands up in a gesture internationally recognised as "stop immediately" and he says, "I don't do hugs". This lands him in a heap of Larry David-style situations, where mortally offended people ask why he doesn't do hugs; he just replies, "I just don't do hugs". Many think he's being deliberately obtuse, but I don't think he needs a reason to opt out.
Hugging is an invasion of personal space, after all. He's just challenging social norms. In fact, I might get him a T-shirt made that reads "Challenging Social Norms".
Compare and contrast this with another friend of mine, who's so eager to establish intimacy that she comes straight in for a kiss on the lips. Every time. She's a wonderful woman in every other way, but greeting her is beyond awkward. You can see it coming, and she knows perfectly well what she's doing; there's almost a gleam in her eye as she approaches. From that point it's a fiendish game of physical strategy, nerve and skill, as she remains intent on achieving the kiss while you try your best to avoid it, like a game of Lip Taekwondo.
The rules of the game permit neither of you to acknowledge that a game is underway; you've just both got to do your best. If she gets the kiss, she smiles triumphantly; if only a cheek kiss is secured she looks vaguely dejected, while her prey performs a mental lap of honour.
These two friends of mine have, thus far, never met. The dream, of course, is to get them both into some kind of Large Hadron Collider of social awkwardness, sit back and watch it all kick off.