Its called HALO EFFECT.... That's what you always base your judgement on, halo effect isa generalization from the perception of one prominent or salient characteristics, trait or personality attribute to an impression of the personality as a whole, which leads to inflated correlations between rated characteristics..you really need to look deeper beyond just his looks and check other attributes for your self and not assuming that because a guy is handsome for instance, that he will be humble, smart and all what not.