The first is not getting what you want and the second is getting it.

This rings true especially in the case of women. You know the deal; you meet a seemingly nice girl and get involved then later realize that she really isn't any different from every other girl you've come across (silly you for expecting any different).

Or when you wanted a particular job so bad and after a while you finally got it , which led to you hating waking up every week day and living for the weekend.