I've been wanting to die for years

[S_Spartan]

I love how American society is always putting ideas in our heads like "you need to strive for perfection" or "if you aren't feeling joy most of the time then there is something wrong with you" then you look at society as a whole and it's a hot mess of misery.

 

[theslowesthand]

There are no irrational beliefs in relation to my future. I've got some problems that have become increasingly worse in time and will continue to do so no matter what.
...
What do we consider irrational beliefs about what life ought to be? Is it irrational to want to have an enjoyable job that doesn't make you hate your life from Monday to Friday (and probably beyond that)? Is it irrational to wish for an average social life?

Facts are facts, and it seems you may be correctly seeing the reality of your situation as it really is, so no "errors" there in your thinking.
But another fact is, that your unhapiness/misery/etc is not actually due to these practical facts or realities. Neither is it due to what other people say to you, or how they treat you. And (if i'm not mistaken) it also isn't due directly to having an inadequate (for you) social life.
What i'm saying is that it is possible (though might not be easy) to have at least an okay level of wellbeing no matter what your life is like, or has been like.

I've never understood what "enjoying little things" means. I mean, in order to enjoy little things you have to at least be content with how your particular "big things" are. That is, if you're happy with your whole life, you'll be capable of enjoying even the most simple things. Instead, if you're unsatisfied for whatever reason, you won't turn into a happy person even if you get to enjoy a lot for a certain amount of time

By "big things" do you means areas of one's life (ie health, financial, career, relationships, etc)?. If any of these areas or needs are not being satisifed, i guess it may make it harder to enjoy the litlle things. Is this what you're meaning??.
What i mean is for example feeling happy at end of work day to be home & say having cuppa & read magazine. Or to gain a sense of satisfaction & accomplishment at tidying a messy drawer, or cleaning a sink that was dirty. Watch your favorite tv program. Or to feel a moment of peace and serenity whilst looking at a stunning sunset.

Do you really consider joy to be a natural state of us humans? Aren't we rather forced to feel joy even when our lives mostly provide us with stress and constant worries?

Joy comes naturally to all sentients creatures (humans, animals,..), as far as i know, if they are healthy. Society & the media i think do seem to be pressuring everyone into being happy-chirpy-joyous, when everyone knows it's not reality. But actually they are kind of on the right track, as hapiness/positivity/etc are "good" things to have.
And it's unnatural for humans to be having the amount of stresses/worries they have in today's world. But that's how life is at the moment. However there are ways and means to minimize these stresses, and the handle the effects of these stresses (in healthy ways).

Wishful thinking here.

There are bright, interesting, beautiful people who graze perfection and there are others who simply don't stand out at anything. Traits are not distributed equably and some roads to perfection are way longer than others

I'm not really talking about perfection per se, but more about "chipping away" at one's flaws & problems, day-in-day-out, year-in-year-out.
Most will never reach even remote perfection, in their character, mental health, or life.