Where does fatique come from?


I've heard systems in the past (also owned them ) that would fatique your ears after a certain amount of time. Always thought this was the speakers fault. Is this right? or a combination of Speakers, Receivers, Cd players, Etc. How much do you have to spend to get over the fatique factor, or is just personal to each person?
Gary
garypic
Recordings can also be to blame. Some stuff on my system just makes me want to get up and turn it off, Sarah McLachlan, "Surfacing" comes to mind. I like her stuff, but this CD just sounds harsh. Then there is stuff I can just listen to for hours.
Reading all the spelling and grammer mistakes ( including my own ) here on Audiogon