On the topic of ear training and hearing differences most people don't hear, I had a recording I was mixing down that featured a squeaky kick pedal on the bass

On the topic of ear training and hearing differences most people don't hear, I had a recording I was mixing down that featured a squeaky kick pedal on the bass drum. I spent more time than I should have trying to scoop that out of the mix, and in the end, I could still hear the squeaky kick pedal, but no one else in the band could. Later that week I put in a CD with songs I'd heard hundreds of times, and to my absolute horror, I could now hear the squeak of that drummer's kick pedal, like an icepick jabbing me in the ear. It had been there the whole time, pressed to millions of CDs, broadcast over countless radio stations, but only became apparent to me after intense focus on that particular sound. I imagine that people who claim to hear the difference between 320kbps and lossless experience something like that. There may be a particular, narrow band of frequencies that sound slightly more modulated in 320 when compared to lossless, but unless you make a concerted, drawn out effort to find that, you'll never know. And if you do make that effort, you can end up ruining your otherwise pleasant experience for absolutely no good reason. Anyway, after the kick pedal squeak incident, I switched to listening to wholly electronic music for the next month or so as a palette cleanser, and I haven't picked up on the squeak anywhere else since.