I agree ... sound is in our brains not our equipment. The way we perceive things changes with moods, fatigue, time of day. I suspect this effect is also responsible for much of the "burn in time" required on solid state electronics.
Sound quality vs. Mood
I've been trying to get a handle on why my system sounds so much better some times than others. The most common explanation would probably implicate the quality of my power. That could very well be and as soon as I can afford to experiment, that's what I'm going to focus on. However, I've always suspected that mood has a huge effect - maybe the largest effect - on subjective sound quality. Any thoughts?