Is the reason why I am not approached by guys is because I'm either overly good looking or unawarely ugly?

Probably you don't make eye contact. Or smile. Or both. They're go at anything that looks at them, especially if it smiles!

Impossible to even guess without seeing what you look like. Even then it'd just be one man's opinion. You sure you don't already know exactly why they don't and you're just looking for validation of your own self judgment?

Either way it's only your own fair assessment of your situation and your level of self esteem and self worth that mattes. That and committing to make whatever changes you are will to make to get the results and feeling of self satisfaction that you want.

I always liked a girl that looked different, the beautiful girls are just a pain to deal with in real life.

Be yourself, someone will discover you eventually.