I was thinking about the phrase "Absence makes the heart grow fonder." I've never liked the phrase, I think its rubbish. Absence makes the heart forget more like. And in some weird, twisted way, the two sayings are the same.
The reason absence makes the heart grow fonder (keep in mind, this is my theory) is because the more time you spend apart from someone you care about, the more you want to think positively of your time together. When you focus on the good parts of the relationship, you forget the little things that drove you crazy. In your mind, you put the other person on a pedestal, and by doing so are more reminded of the good. And so, your heart grows fonder. At the same time though, you are forgetting those little faults that make people human. So, in a sense, the heart does grow fonder, but that's because it forgets.