One of the reasons I use EQ is because my right ear is messed up. I have to dial down the 4-6 kHz range in the right channel as these frequencies are distorted and painful for my right ear. Other than that, I sometimes add a subtle bass boost on certain headphones because I feel they benefit from it. There's nothing wrong using high quality equalization (by high quality I mean it has to be reversible), your audio has been eq'd many times during its production anyway.