Most Helpful Girl
Sometimes, when you break up with a guy because he's done something bad, he becomes ugly. To lots of people, somebody hot who has a disgusting side to their personality, you start seeing it in their face and they start looking ugly.
Also, in a relationship, lots of people are looking at things with rose tinted glasses, thinking it's better than it is. When they leave and take those glasses off, you suddenly notice how wonky their nose is, or how their eyes are so close together or whatever it is