Short post, but one I don’t think needs a lot of explaining to get the point across.
A guy meets a girl on the street. He likes her; she seems to like him. They talk for fifteen minutes or so and get along just fine. He feels like he ought to do something more with her… but he isn’t sure what, exactly. So, he asks her for her phone number, tells her it was great meeting her, and the two part ways.
Chances are, they never see each other again.
Sure, maybe they do, but odds are they don’t. How many of the phone numbers you take turn into lovers? Even if your follow-up is amazing, your conversion rate of numbers-to-lovers is doubtfully any higher than 20% – maximum. And if your follow-up is anything short of amazing, expect a conversion rate substantially lower.