Let me clear this up for you

For me, Sci-Fi is about the hope of a better future. In those stories, people explore beyond our petty problems of the past.
- Not much of that utopian sci fi around though.
  
  There's some hopeful sci-fi on it's way soon with Starfleet Academy.
  Mostly looking forward to the return of The Doc.
- Yeah I guess there's two different categories of sci-fi in this regard. Personally, I think stuff that's as far ahead in the future as Star Trek is pretty close to fantasy. But then there's also the Philip K. Dick style near future dystopian sci-fi that serves more as a warning about the future we're headed to (or instruction manual if you're a techbro CEO).
  Fantasy is probably the same actually. I usually think happy thoughts if I think about fantasy as a genre but then there's also stuff like Game of Thrones.
- At this point in our development, we are like new born babies .... in a few hundred or even a thousand years, we'll be like toddlers.
  When you look back on our human evolution as a species, our first ancestors came about two million years ago, the ancestors that look like humans are about 100,000 years ago and the ones that would most closely resemble us and our way of thinking is about 50,000 years ago. We've only been technologically capable for the past 150 years. When you think about it, we are closer to our frightened, superstitious, ignorant prehistoric ancestors than to any futuristic culture we would like to emulate.
  It's going to take us generations and centuries to get to the point of being a contributing participant in a galactic community. IF we can survive that long.
  "I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."
  Isaac Newton
  ....... but saying all that, I don't mean to be disparaging or negative ... just realistic. In the long run of human history, it will be through people like you and this community of hopeful people that enjoy playing in these ideas and possibilities that will take us one step towards a more hopeful future.
- 'O brave new world, that has such people in 't!'

Flaw number one: sci fi can be a lot, tonally. It can be depressing, but also hopeful, horrifying, epic etc.
Flaw number two: fantasy can be a lot, tonally. It can be depressing, but also hopeful, horrifying, epic etc.
Flaw number three: "literature" is not a setting. There's fantasy and sci fi literature as well as real-world-related or apocalyptic literature. "Literature" is just written down stories.

I don't think sci-fi and fantasy are that clear-cut. A lot of fantasy is quite hopeful (the bad guys pretty much always lose at the end of the story), and it's kind of 50:50 whether it depicts the past as better or worse than it was. e.g. the shire in Lord of the Rings is practically a utopia, despite not being completely unrealistic for a pre-industrial society (it probably looks a lot more utopian than it is because most of the hobbit characters we know are aristocrats).
Literature is, generally, definitely not about happy feelings, though.
- This is Farmer Maggot erasure and I won't have it

If every genre you read is depressing, you're the common factor.

That's my secret, Cap. I'm depressed about the past, present, and future at the same time.

For Conservatives these days ....
Sci-fi is their fantasy
Fantasy is their reality
and literature about dystopian futures is their guide

Sci-fi with depression replaced by hopefulness = Star Trek.
- Literature with depression replaced by hopefulness = solarpunk?
- <3
  You, Picard Maneuver and Stamets are the coolest already just counting the amount of Star Trek content y'all make/share.
- The Culture
- Sci-fi with depression replaced by hopefulness = Star Trek.
  Only because everything problematic about Trek is written off by fans as bad writing and/or it being a product of it's time and/or it being a film, and any opinion to the contrary is considered deeply offensive fighting talk.
  Not to mention the fan base can get hella toxic too, the Micheal Burnham Discovery era was not a fun time to be a fan participating in episode discussions.

Uh, did I always use the word "literature" wrong? Literature is not a genre... is it?
- No, the OP is the one that wrong.

This is just wanting a pretext to be depressed.
- People need a pretext now?

Sci-fi is what the future could be.
Fantasy is what the world will never be.
Literature is what the world is.

Sci-fi makes me even more depressed because I start to think what we could have now and don’t have because of capitalism

Apocalypse is when you happy about the future.
- Happiness Is A Warm Gun

Split fiction!

You like science fiction because of how it makes you feel about the future. I like science fiction because space ships cool.
We are not the same.

I prefer high fantasy over grim dark fantasy.

Wrong. Scifi at least is about the present. It just uses flashy backdrops and tech to bring you out of your bubble and think a different way about it.

why not all three

Scifi is when you're a fucking nerd who likes technology. Fantasy is when you're a fucking nerd who likes history. Literature is when you're a fucking nerd.
- Since when are sci-fi and fantasy nerds fucking?