There's truth to what you're saying. Everything is technically 'good' by comparison, because there's always something 'worse' out there, and vice versa.
But it is difficult to see that because humans (and to my knowledge all other living creatures on Earth) experience things from the inside-out, and only know- and can compare things to, their own experiences. Meaning whatever a person thinks or feels, is going to be based on what exact habitat they currently live in- have lived in- and what kind of struggles and fortunes they've stumbled upon during that time.
How good/bad people feel isn't based on what happens exactly. It is based on how far this good/bad thing is from their default state of being. Two different people can experience a emotional struggle/lift that is exactly equal in severity, even if the situations themselves aren't equal in severity at all. And as a society that aligns itself on feelings, I think that severity of the feelings should be more significant then the situations themselves. Feelings are valid regardless of circumstance.
People adapt to what they know, see, hear and feel. One person's tolerance for something might be completely differently developed then the next, and thus make him/her react in a different way.
For example;
A rich person feeling depressed and lonely isn't any more or less valid then a poor person feeling depressed and lonely. Many people will demonize the rich person in this case because this person should be super happy because he/she has more fortunes then them, but here again applies that feeling are based on personal perspective. The feelings can be just as intense, and should be considered valid in all cases.
(Sorry for going slightly off topic there. It was merely to emphasize my thinking process behind this.)
I don't think it's necessarily selfish to not-have the first hand knowledge to appreciate something. Lack of knowledge is never selfish, after all. Your experiences in life are for the majority trivial. I also think people would benefit greatly from knowing what good/bad things they have in their life on a concious level, though. Even if just to convince themselves to do something they wouldn't otherwise do with the knowledge.
In conclusion; I agree with what you're saying, but I do think people need to find it out for themselves without being told. Personal growth means little if it isn't personal.
Knowing how to appreciate things others don't see the value/greatness of is a great luxury in life. And I applaud you for figuring it out for yourself.
