I concur with Jez's metaphorical explanation, and was going to post it myself a while ago.
It can be taken further.
The outlet of the water tank can be seen to have a large diameter pipe and the water under the enormous pressure from the tall tank, this being parallel to the O?P of a PS being capable of delivering high current quickly, which will respond to large signals and big transients. (It's O/P impedance is low).
Although mains can be supplied at very high power, the I/P to the tank is in small pulses, those necessary to restore the tank to its 'full' point.
Expectation bias must apply to everyone and in all we do.
We bring to any situation a personal database of our experience which is a 'map' and a survival tool which prepares us.
But it has limits intellectually which in the case of our pursuit, made much worse by the pressure of advertising, which become apparent under scrutiny. Scrutiny also upsets us, often ruining our performance, at least I found this to be very true of me in examinations, the atmosphere of which increased my anxiety greatly.
A man on a gold course who has lost his ball sees a white piece of paper in the distance as his ball, expectation.
Yes we do hear a change most initially, and then we acclimatise, that is also in our biology.
If you put a clamp on your finger and wait, after a few minutes the feeling of it goes, or place your hand in some cold water, the same happens, but on returning to the normal temperature it will now feel hotter.