As everyone who read George Orwell knows, language shapes - or mis-shapes - thought. Hi-fi marketing people aren't fools and read 1984 at school like the rest of us and so they invented, pruned and promoted a pretentious, meaningless and confusing vocabulary guaranteed to bewilder and confuse the weak-minded. For example we read (from head-fi's own dictionary) that
Aggressive - Forward and bright sonic character.
Forward(ness) - Similar to an aggressive sound, a sense of image being projected in front of the speakers and of music being forced upon the listener. Compare "Laid-back".
..How can this make sense? These two things are defined in terms of each other! And what is a "sense of image"? And how, sanely, can we speak of music "being forced on the listener"? Louder I understand; more accurate I understand; higher or lower pitch I understand - but what the devil does it mean when music is more "forced" on me? One can't help bust suspect that this terminology exists to help the salesman's patter when he plays the old trick of upping the volume when he demonstrates the more expensive equipment...
Bright - A sound that emphasizes the upper midrange/lower treble. Harmonics are strong relative to fundamentals.
Well, the first part at least makes sense - "bright" is a pretentious way of saying "emphasizes treble". But the crap about harmonics? How does a piece of audio equipment know that a bit or an electron is part of a harmonic and to emphasize it? How does a headphone resonance chamber look at two waves of equal frequency, one being the fundamental say of the lead guitar and the other the first harmonic of the bass, and know to emphasize the second? Do these people think that headphones echo chambers are occupied by cooperative demons???
Plenty more to laugh at - or despair at - here: http://www.head-fi.org/a/describing-sound-a-glossary