Tbh there's probably a lot of reasons, someone in a psychology field could probably write a whole paper on the subject, but some other things that likely feed into it: Compensating, they know they're grotesque and having an attractive significant other reassures them that they're not Instant gratification, they're just lazy and greedy, they don't want to work on a relationship they just want someone to provide for them Little to no understanding of the human body, explains why they are fat to begin with, but something I like to call "neckbeard syndrome" where a person's expectations are laid out by things like television and works of fiction along with confirmation bias coupled with no self awareness, they expect everyone to be a 10 because it works that way in movies and books and that the ugly main character (them) has to have a great personality to make up for not being attractive My personal favorite theory is the MySpace angle theory where fatasses only want taller guys because he will constantly view them from the MySpace angle and will somehow be fooled.