Even if she was in a good mood to begin with she probably wasn't smiling. I mean, really, who walks around with a sh1t eating grin on there face all the time. The point is you just made her smile and that is all she is going to remember.
Out on the street is a great place for an Instant Date and if she is not available right then you set it up for another time and Number Close.
As for your suggested opener, as soon as 'listen' is out of your mouth she's probably thinking 'line! How do I get out of here" Second, it's to long for a street opener. Women on the street are moving and going somewhere. They key is to grab there attention instantly, not through a 30 second drawn out speech. You're right though, if she is a true hottie she probably does hear it a dozen times a day which puts that line in AFC territory.