If you do it wrong, it certainly does! It took me a while to get good. Luckily Amir offers suggested EQs for a lot of headphones and speakers.
Well, of course, but I was mocking the attitude of the audiophilitics that believe that EQ always ruins the sound. In all cases. Always. I remember when I suggested one of these folks that he should buy a Puffin phono preamplifier and feed its output to a minidsp in order to apply EQ to his recordings to fix some room issues. HERESY! The jagged edges of digital quantisation shall never destroy the pristine purity of his analog records! But, no, the solution can only be trying dozens of expensive and coloured amps until one is found that magically works by equalising in the right way... and maybe picking also the right cables and other accessories to "fine tune". Sigh...