Plenty of technical discussions about h-fi on the interweb but you will always get someone who crops up to say something like:

'Did you listen to it?'
'What it sounds like is all that matters'
'I just use my ears'

And so forth.

What's more these statements will be made with a bemused/confused tone. As if it is obvious: If it sounds good it is good, why complicate what is so simple? The logic is straight-forward.

Or so you would think. However 'Just listening' has some major drawbacks when used as the sole method of evaluating a piece of equipment or even a format. If you don't, or are unable to put what you are hearing in context, you can end up making some wrong assumptions, and consequently make some poor buying decisions. Whilst it is always pretty clear-cut whether we like the sound we hear or we don't, making any further assumptions solely from that input can lead us down a garden path. Here are some examples where 'Just Listen' falls over:

1) Manufacturers don't always tell the truth, at least not the whole truth. You hear a component and like what it does, The maker says the reason their X sounds better is because they use Y technology in it. So you jump immediately to the conclusion that anything using Y technology will be good, that Y tech is ground breaking, a paradigm shift etc etc. Whereas in reality Y tech is just marketing babble and the reason that X component sounds good is simply that it is well engineered. 'Well engineered' is, depressingly, not a concept that marketing can sell in the modern age. Hence the need to emphasise the use of Y tech. Will all components using Y tech sound good? No. Only the well engineered ones.

2) Something could be broken or not performing optimally but you don't know this. You try X amp in your system, doesn't sound very good. You don't buy it and you tell everyone 'yeah, I tried X amp, it isn't up to much.' 6 months later you discover there was a fault with your speakers, or your cartridge was out of alignment, etc etc.

3) There is an incompatibility between X and the rest of your system. You don't know this because you didn't check out the spec first, you 'just listened'. Again you don't buy and if asked you tell people that X is not up to much. In reality it did not have enough gain for your amp, or it was underpowered for your speakers, etc etc

4) You 'just listened' but you didn't listen enough. A few audiophile recordings does not a summer make. Did you try every genre of music? Every time period from early 1960s simple recordings to modern, digital multi-tracks? Music with loads of deep bass? Music with close-miked female voices? If the equipment (especially loudspeakers) has a flaw you may need to listen to 40 or 50 different recordings before you notice it. Once you hear it on one recording you hear it on them all. Equipment is rejected, but at a great cost in time. (plus your 14 days to send it back has probably expired).

5) You can be the problem How much we enjoy listening to anything is dependant on our mood and a host of other factors we cannot always verify. Whereas I am personally of the opinion that 'expectation bias' and 'placebo effect' are totally overblown as excuses for why we perceive differences when there should technically be none, we still can't escape from the fact that if we listen to a good system in a good frame of mind the experience will be much more impactful than if we are listening when tired, depressed, have stuff on our minds, or when it is a chore and we would rather be doing something else.

You might have memories of a particular evening at a friends house, playing music all night, the sound was amazing. You mention it to a few people, maybe even think about replicating that system for yourself. Some months later, you go back for another listen, same system, same music, it sounds utterly prosaic. What has changed? Mains quality? Or you? Which is more likely?

'Just Listening' is just not enough.