As I've said all along, I'm not a fan of the concept of 'underrated' or 'underappreciated' art. It seems to me that any work of art gets exactly as much appreciation as it deserves. To argue otherwise is to argue that there is some absolute standard of artistic value to which some people, mysteriously, have access, while others do not. To claim that something is 'underrated' is merely to say that our own tastes differ from most other people's.
While I don't want to get in a big debate over the idea of "absolute artistic merit" I will say that something might still possibly be underappreciated for other reasons. I'll just give one.
Think about it: one individual record company exec decides to heavily promote one song, get it played on the radio, release as a single, etc. and so this song enters the public consciousness and is better known than another song. But if that other song has merits and the potential
to be popular and well-loved, maybe even more
well loved than the single that was released, we could argue that the song is underappreciated simply because it also deserved the chance to be promoted heavily, to find its level of success. Maybe deserved isn't the right work - it just had potential equal or greater to another song, but didn't reach that potential because of the decisions of one or a few people.
On a more basic level, of course it's all about our own opinions - when I call something 'underrated' or 'underappreciated' I can either mean simply that if things had been done differently, the song had the potential to be better-known or even become a radio standard (which I think, based on the economics of popular music, is almost undeniably possible for many songs), or on the other hand in a more important way, when I use these terms what I am saying is that i find meaning, value, beauty, or something else of worth in a work of art that I believe others may be able to value too but have not, either because they don't even know about the existence of it, or because some people just tend not to focus on things which - if they did
- focus on, they would enjoy more.
It's all opinion, of course, as is almost any discussion of art if it strays away from purely practical applications of it (one could have a legitimate, quantifiable discussion about which of two songs is, on average, better at getting people to buy more if played in a supermarket; but any discussion about which of those two is better is going to necessarily involve opinions, even if it is only in choosing what criteria determine 'better').