just think about a real life situation with your friends. they all wish to do something(sleep with that super hot girl you all know that won't even give any of you the time of the day, go skydiving, win a million bucks with a lottery ticket, whatever), but they haven't for many reasons. you tell them that you did all that and can do it anytime you want. your friends might be entertained and maybe even impressed for a minute, but at some point they will expect you to prove that you're not full of crap. and if you never bring them supporting evidence instead of "dude trust me", soon enough you'll become known as the mythomaniac of the group.
exact same stuff here. when bigshot says he can't tell between high bitrate AAC and a lossless format, if that's bragging, it sure is a weird way of doing it. the guy shares his failure to notice a change. I'm in the same situation and so are a many people here. so when you come bragging about how easy it is to notice a difference between basically anything and anything else, well, we're the others guys in your group of friends starting to think that you're full of it. to change our mind you could take back what you claimed, or provide strong enough evidence to support the claims and convince us.
and that's about it.
and in case you decide to assume that me posting this is a denial of anything possibly sounding different ever:
I've noticed differences between DACs(volume output, very rarely background noise, on super rare occasions a massive roll off in the treble). I've heard high bitrate mp3 sounding strange, never very obviously so, but enough to be noticeable(massive intersample clipping, or the device messing up the decoding on the first firmware version for the DAP). and I most certainly heard differences between various DAPs or cellphones(I basically just have to pick the right IEM to manifest the most difference in background noise or in impedance output). I also broke my arm, got bitten by a monkey as a kid(not radioactive
). all of those things happened and were supported by controlled testing or many eye witnesses, but it's not like they happen to me all the time. some are extraordinary occurrences. and for most of those situations, it's fairly easy to reduce the chances of it happening even further without resorting to total paranoia and getting rid of everything that remotely looks like a risk.
for example, I don't play mp3 at full scale, and I haven't met a monkey in a decade. thanks to that I didn't feel the need to stop using mp3(and other convenient lossy formats), or to go out only with a chain mail over my entire body in case there's a monkey down the street waiting to jump on me. ^_^
of course if you don't have a clue how to test anything conclusively, you will tend to have an even bigger problem. the problem called "being wrong".