Well.... Since you asked... I think it complicated. See below....
I can only comment on white wines, since that is what I make (well... I do make Amber wine but that is another topic). And to fully clarify my position I really dislike the American ideal of wine.... Way too sweet. The total concept of back sweetening a wine. Eww. Common in the USA, but pretty much only in the USA.
So, knowing where I stand, to that, what someone in the USA calls "bitter" may not be "bitter" to another wine drinker in another country. Thus this is the first issue to consider. I for one like a bit of astringency in my wine. And rather dislike sweet wines oh too popular in the USA. Tastes differ as to what is "bitter". And, no, for reference, I thus do not like Tokaji wine.
As for YAN and mercaptans, when I have had mercaptans in my wine, the wine was flabby and dull. Not bitter or acidic or astringent. I have never measured my YAN (in fact, I do not adjust my wine or my vineyards), but I do measure my yearly environmental factors. And different years, with different weather, do create different wine, with different amounts amounts of bitter, sweetness, etc. etc. etc. That is a lot has to do with that year's environment in which the grapes are grown. That is... the age old idea of a "vintage". Some years will be different than others.
One has two options (or more --- I do not want to create a false dichotomy, but these two are the ones to most consider):
1) Spend a lot of time and effort to try to correct the wine in the cellar to make it want you want it to be.
2) Let the wine be what is it, and enjoy it for what it is. A vintage.