I'm trying, really.

See, I can walk up to anybody and introduce myself.  No problem.  I did just that earlier tonight.  After my friends had left the bar, I found the one unoccupied seat and plopped down next to a reasonably attractive young woman.  She looked bored off her ass, so I said to her, "You look about as bored as I am."  She said "Yeah, I kind of am."  So I said "I hear ya.  But I figured I'd rather stroll over and be bored here than bored at home."  Before my wit could generate a snappy follow-up, she gave me an awkward chuckle and turned her back to me and her attention to the admittedly significantly better-looking "bro" types loudly inhabiting the end of the bar, high-fiving each other with their muscles and tight t-shirts.

My problem isn't initiating conversation.  I can do that all day long.  Where I choke is when it comes to plucking  profound and intellectually stimulating conversation out of thin air to some total stranger that I don't even begin to know, within that five second window between "Ok, I'm listening." and "Ok, you're creepy."