[Dante Hicks]

Prevention is better than cure and so I tend to not acknowledge people at all if that's feasible. Saying hello seems to encourage people thinking they might get some sort of human warmth or friendliness in the future, which is unlikely to be forthcoming - so why unnecessarily build expectation?

If completely ignoring them isn't an option then I'll slightly nod the head and glance in their direction (possibly couple with a very brief "alright?". Shaking their hands isn't something I particularly like doing but if someone has come to a place to meet me (e.g. for a business meeting) then I'll do it as it seems to relax them.

If I am meeting someone in a club (and I'm therefore intoxicated in some manner) then I'd probably shake peoples hands (even females) if I'm meeting them for the first time. If I'm being re-introduced to a female that I've met before then I'll probably hug them depending on
a) if their body language implies this is what's desired.
b) a quick mental calculation on how much I want to put my hands on their arse. If this isn't really on my current wish list then I'll probably give them a rather impersonal hug with my hands patting their shoulders. If it's someone I know well then arms need to be securely fastened around them as they may be their sometime in some rather pathetic display of emotions.