Thanks to Natalie for pointing out with specific examples and evidence that I have an adversarial relationship with hugs. I have several problems with hugs:
(1) I always have a problem deciphering whether it's a hug situation or a fist-bump/handshake/other form of social greeting/departure situation. Then if the other person isn't on the same page as me, we really have a very awkward situation.
(2) Full on hug or half-ass out hug? See beginning of "Wedding Crashers" to summarize my opinions.
(3) How long should the hug last? You don't want to be rude and give too brief a hug, but you don't want to be inappropriate and give too long a hug. And there is also the issue that what may be an appropriate length hug to me may not be to the other person.
For all these reasons, I prefer to avoid the hug when at all possible, and opt for handshakes for formality and fist-bumps/high-fives for informality, as they cannot be misconstued. But I know that I must start incorporating more hugs as it's a very popular form of social greeting as you age, so your moderator will work on improving.