The "look"

This is a problem that I feel presides over the human (single) race like a nasty, nasty plague! Let me get you on the same page as myself. Imagine yourself at your favorite coffee shop, personally, I love the one down the street from my apartment, and you notice a cute guy reading, drinking coffee, smoking, eating, etc… THEN, he looks up from his mid day break from reality and catches eyes with you. Both of you, slightly shy, smile at each other; lock eyes for a split second, then... nothing. He looks up at you several more times, finishes up what he came there to do and promptly leaves. Of course, not before giving you one last giggle grin to set your heart turning and your brain trying to figure out what all those looks meant. There was no wedding ring. Maybe a girlfriend? That is, possibly, one of my favorite scenarios. What’s a girl (or boy) to do in this type of situation? Should you follow him and express how much you have fallen in love over those five luscious-eye-locking episodes?
I have encountered situations where the guy doesn’t leave. The looks turn into audible questions: “come here often?” type stuff. However, my question today deals with the scenario when the guy seems cute but shy. You just know that he wants to meet you. Should you wait for him, or make the first move yourself? You don’t want to seem pushy, but maybe he is worrying about the same fear. These looks can happen anywhere. I tend to stick to the “feeling technique” if it feels right do it. However, that can end disastrously too. That’s really all I have to say. Should you go talk to the guy or shouldn’t you? I don’t know. It’s too hard to decide. I can never really tell what the guy is thinking. Can you?