I’ve never been able to reliably tell a difference between FLAC and 320k MP3 files

I just keep FLAC around so I can transcode them to new lossy formats as they improve. And so I can transcode aggressively for my mobile when I'm streaming from home, and don't need full transparency.

Yeah there's a clear difference between a pair of $25 or $50 headphones and a pair that cost a few hundred. When I first got my Sony WH1000-XM3s I let my coworker try them and he said "Wow, I didn't know music could sound this good!". When I upgraded to the XM4s a few years later I let my brother try them and he was similarly impressed.

Beyond a few hundred and the thousand dollar range you hit diminishing returns.

Blackmail -- Evon. That's the one song where I ever heard a difference, though that was ogg, dunno what bitrate I used back then but it was sufficient for everything else. Listening on youtube yep that's mushy. The noisy goodness that kicks in at 0:30, it's crisp as fuck on CD.

...just not the kind of thing those codecs are optimised for I'd say. Also it still sounds fine, just a bit disappointing if you ever heard the uncompressed thing. Which is also why you should never try electrostatic headphones.