Principle of Least Interest
In a two-party relationship, the party exhibiting the least interest in the relationship holds the most power. This is due to the (albeit often false) presumption that relationships are an efficient economy, and that one party would only be more interested if the other is inherently more valuable.
Johnny wanted to send Daphne flowers after their first date, but since he asked her out in the first place, the Principle of Least Interest dictates he will be more likely to score with Daphne in the long run by waiting for her to make the next move.