Why do guys check a girl out without following through?

Okay, so a guy will be checking me out, and then... nothing! Why is it that guys will check a girl out, sometimes repeatedly, and then not approach her? Why do some (most) guys not follow through?
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+1 y
Okay, I think I should expound. If I see a guy checking me out and if I'm interested in him, I'll always give him me sweetest, forthcoming smile (or at least I try, haha) That's why I can't understand why he then doesn't bother to approach me. Isn't a smile the so called "green light?"
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+1 y
Thanks for all the answers, definitely some great points made!
Why do guys check a girl out without following through?
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