The whole point of an eq is to tweak the sound so that it sounds good (as opposed to look good) and what sounds good to one person's ears might not sound good to someone else's.
For example, older people cannot hear higher pitched sounds as well,
so they would tend to raise the eq settings for the higher frequencies.
Or if they had advanced hearing loss,
they would not be able to hear the highs, no matter how high the treble...
A younger person might turn on an older person's radio and say, "jeez where's all the treble?"
and raise the treble, while the old man who's car it is percieves no difference in the sound.

Well anyways, that's my 2 cents...