I know you know I know you know me

Despite my dry life commentary I like to think I'm a reasonably pleasant guy to talk to in person.  I'll laugh at your mediocre jokes.  I won't leave you hanging if you go for a high-five because you think StarCraft II is "totally awesome".  However, there are certain social interactions that I will not tolerate which make me want to drop a cinder block on my tool.  On the like/dislike scale I'm talking "I would rather put razor blades in my already lacerate-capable Captain Crunch than deal with this".

One scenario in particular that straight up infuriates me is the following:

Imagine that X years/months/weeks ago you met someone casually in passing.  Maybe it was a friend of a friend or someone you share a class with.  Hell it could even be that guy who always gets the same prostitute as you on those lonely Saturday nights when Call of Duty just doesn't make you feel like enough of a man.  Your introduction to this person is brief but pleasant.  Names likely aren't exchanged but pleasantries most certainly are: weather, the economy, favorite positions with said hooker etc.  Anyway, the meet and greet goes down and everyone goes on their way.

Back to the present - you're out at a bar with your friends and you see the same person regaling somebody with a story about "that time he had a piece of broccoli stuck in his teeth for a whole week!" because everyone always seems to find that story so funny...

In spite of his veggie tales you decide, beyond all quantifiable logic, that you want to solidify your relationship with this person as your friend and/or Eskimo brother.  Time to down that amaretto sour, He-Man, it's guy-flirting time.

"Hey man! I bet Raquelle was surprised when you pulled the Turkish Snowcone Maneuver AM I RIGHT?"

"What? Do I know you?  Turkish who?"

Are you being serious right now, Semi-Anonymous Street Corner Patron?  There is a 100% probability that he is the guy from before and you're 95% sure that you both share the same STD - you two have a bond and he fucking knows it.  Remembering a face is about as difficult as getting morning wood.

I don't understand why people feel the need to pretend like they don't know you just because you aren't fully familiar.  What is so awkward about saying hello to a vague acquaintance?  You know what is awkward?  Going up and blerfing out a phrase like "turkish snowcone maneuver" with the expectation that it will be met with a hearty "lol what's up" only to find this dickhead has decided to make you feel more out of place than a Tim Burton movie filmed in the full color spectrum.

What puzzles me most about this move is that I don't see what the other person gains from it.  They don't look any more popular by not knowing me.  They don't establish themselves as the alpha-friend by not knowing me.  And they sure as hell don't get my pity laughs/high-fives for their stupid stories by pretending not to know me.  Will somebody please enlighten me as to the benefits of feigning amnesia?  And if there aren't any, which I suspect is the case, then fucking stop it.