I thought that "night and day" was expectation bias. does that mean night and day different=a tad=0.07bananas?
the case of balanced cables is a little peculiar as it also involves a different output or even a different amp sometimes. so just dismissing the possibility of an audible difference without more information may be a little hasty. of course the most likely difference is loudness and whatever impact the change in impedance has on the headphone. so that much should be checked before drawing conclusions on what a balanced cable does to sound. but even if it's only that, the listener is indeed going to perceive a change in sound, so that much must be acknowledge.
of course having better hearing or simply being more able to notice specific variations thanks to experience, could explain why some people notice things that other do not.
just like having something looking different or having a significant difference in price, can be enough to force the brain into believing that the all experience is different, including sound even when there is nothing audibly different. we suck real bad at isolating our senses at will, and that's been confirmed so many times in so many ways that it's just irrational to dismiss the possibility.
or it could be that the main electrical change is a difference in loudness, as I mentioned above for balanced vs single ended experiences. then there is a clear and very real change in sound indeed^_^. it's simply not something worth paying for when we could get it by slightly turning the volume knob on the other gear.
or...
there are several possibilities, so the important thing IMO is to be able to confirm which one concerns our own experience. and to do that, we need a properly controlled experiment. that way we hopefully get the truth. which IMO is better than cherry picking the answer that satisfies us, declare it truth, and then treat those who cherry picked something else as if they were silly puppies. unreliable experiences are unreliable no matter if the guy ends up agreeing with me or not.