Sam.  You are 26 and single.  If by the third time you see a gal she is still talking and smiling at you and you think there may be a little energy there - ask her to meet you for a cup of coffee or a drink  or something.  Keep it casual, like - "Hey, I'm gonna grab a cup of coffee over at _______ after work.  Want to meet me there?"  If she sais no, then tell her "Maybe another time."  And leave it alone and never offer again.  Just be polite and kind,and brief.  If she is interested, she'll bring up the cup of coffee.  

In the mean time, get a hobby.  Keep your mind busy on other things - it happens when you least expect it and definitely when you are not looking.

Hugs and hope for a nice, attractive girl.

here is a huge hug for u sweetie...much love and huggies

I must agree with what the good folks have said before me.  Lighten up and enjoy the flirting and fun of these lovely ladies.  Take a chance & ask about coffee or something... Maybe don't be so defensive and analytical.  Lots of people talk and flirt and don't even know if they are "interested" until the opportunity to be interested is presented.  Good luck and keep smiling!