I've found that some people inherently have good listening skills for discerning differences. For people around me, I've found that my mother has a particularly sensitive ear. I think my son does as well.
Despite not having listened to a whole of high-end audio, my mom can hear something and describe what she's hearing exactly as what's in my mind. I think people that have those skills for discerning differences, especially if they are not audiophiles that get all caught up in what the equipment "should" sound like are very helpful for overcoming the confirmation bias of thinking something might sound better or even different when it does not.
My wife is not into audio equipment at all, but by observing her responses to what's playing, I can learn a lot about the sound quality of the equipment that I'm testing in my system. She seems pretty attune to harshness. If she says 'your music is too loud', I will see if my actual volume is loud or not. If my music is on at a low volume level, I can tell that a digital component has some level of harshness (perhaps due to jitter or analog noise coming into the system). Also, if she starts singing to music that she likes, I can tell that equipment is doing in terms of being able to "follow the tune".
FWIW, I've been putting together a digital front end and my choices seem to all be trending in the right direction on this 'spousal acceptance test'.
WiFi > Ethernet (WiFi turned off)
Ethernet cable
USB cable
Addition of an Audioquest Jitterbug noise filter to the USB output
DACs: Denafrips Ares II > Chord Qutest > Chord Qutest running off of a battery > Denafrips Pontus II
