So you're chatting up a girl and everything seems to be going well. She gives you her phone number before running back to her friends. "Call me", she says with a mischievous twinkle in her eyes. So how long do you wait to call her? Your first shit test has already begun.

Here Barney Stinson tries to explain to Beta loverboy Ted on why you wait three days to call a woman. (Regardless of your opinion of the sitcom you can't fault the TRP logic)

In the scene, Barney goes on a humorous tangent on why Jesus waited three days before resurrecting himself before the people of Nazareth. The citizens simply wouldn't have appreciated the 'miracle' had Jesus been resurrected the following day. In an analogous fashion, by waiting a few days to call a woman, you build self-value through anticipation. Yeah she was attractive, but you're a patient man with many creeks to drink from (i.e options). Note that this doesn't necessarily have to be options in the form of women. You're just doing whatever you may find enjoyable. Meanwhile, the suspense is building up and she is hamstering over all the superficial reasons why you haven't called her. I'm not faulting her, it's simply how the female brain works. That's what makes that call all the more meaningful when you decide to make it.