I'm serious. If you are a girl in that position and someone clearly likes you (or at least is putting a lot of messages out there) and then makes it clear that you're somehow "too high" for him, you can end up hating your intellect. You can feel like being at all smart is a big fat burden and it makes you unattractive. You can start to tell yourself that you're not particularly attractive physically and there must be something wrong with you even if objectively that is not the case. Etc. You do feel judged if you're a girl in that position and you actually do like the guy. It's not a pleasant feeling.
If she acts like she's too good for you, that's another story. But seriously, if she does like you and you go off and find yourself a dumber, uglier girl (being blunt, sorry), there is a good chance that she will be really hurt, feel like an idiot, and end up disliking you.