Is "You're too good for me." the biggest crock excuse a girl can give a guy?

Some girls just have a hard time keeping their self-esteem at a level where they believe that they are "good enough" to be with a certain guy. We guys know that excuse isn't true, but because of social pressure and maybe even people close to them putting them down, some girls don't allow themselves to experience how good things can be. They are afraid of being hurt so they don't want to take chances.