Despite arguably being worse than the Olympians, the Titans are said to have established a 'Golden Age' where man wanted for nothing. Thanks a bunch, Zeus.
To be fair, many would be very pissed off if their father ate their siblings and tried the same to themselves.
Then there's that whole slave to fate thing, so it's not like he really had a choice.
The ancient Greek word for "safe" translates to English as "free from fear". Their word for "safe" meant that they weren't in danger. It's a negative. To them, the default state of existence was "not safe".
One last thing that cements Greek mythology as being this trope: There is a reason that Hope is one of the things in Pandora's box. The Greeks believed that it was just as bad, or even worse, then all the other ills in the box, because it deludes people into thinking that they don't live in a Crapsack World, only to crush this belief utterly.
Sumerian Mythology only seems to have one afterlife destination, which is a dusty, barren and empty hall described as sucking immensely. The entirety of The Epic of Gilgamesh is an ode to the concept that dying can only result in endless tedium and suffering. Also, the goddess in charge of the place routinely threatens to unleash the angry, bored dead to fuck up the living world if her father, the head honcho god, doesn't agree to her arbitrary whims.
Also, the pain of whatever killed you in life carries on eternally in the afterlife. Ponder that for a moment. There are ways to improve the general shityness of the afterlife, however. First and foremost is having lots of children. Having few, or no, children will severely increase your suffering in the afterlife. The reason for this is unexplained, but one would assume it is related to the lack of grave offerings or something of that sort. There is also the possibility of being upgraded to godhood upon death (which happened to Gilgamesh himself in one of the Sumerian poems) which will give you a small part of the underworld to reign over and possibly improve.
The Aztec afterlife required you to run a big damn gauntlet to get to it, at which point... you spend eternity sitting around inside a pyramid, doing nothing, only even getting to eat on the Day of the Dead. On the plus side, you can read the life stories of everyone else who got there, maybe write your own.
If you think the afterlife was bad, in life the god who controls the sun is a bloodthirsty, warmongering psychopath. If the Aztecs do not constantly war with other tribes and perform grotesque human sacrifices, he will refuse to let the sun rise and the entire world will freeze.
To be fair to said god, it's not spite: he'll starve if he doesn't get the necessary hearts. And according to one version of the relevant origin myth, he sacrificed himself that the people of the earth could live to become a sun god. Sometimes all the gods except the wind sacrificed themselves to fuel the ignition of the sun and have no bodies but the temple statues, and so require much blood to persist and protect.
Should you die in Pharaonic Egypt, you have to take a very long walk across the desert (hope the people who buried you put a map in your tomb), at which point your heart gets weighed. If it outweighs a magical feather representing Truth, its get thrown to the beast Ammit, who eats it and condemns you to Cessation of Existence. If the feather outweighs it ("We made it really heavy"), you get to... work in Osiris's fields for all eternity. Hep hep hooray. You get to do what, in all likelihood, you did for your entire mortal life.
Not quite. Initially, only the Pharaohs got an afterlife. Later dynasties would expand the afterlife to all the nobles. The commoners who would actually work in the fields got nothing.
This isn't quite true. There just isn't a detailed guide to how ordinary people's afterlife will work, like with the Pharaohs and nobles. Even the commoners were mummified, albeit in a very simple manner, so they must have expected some sort of afterlife for themselves. But that's the ticket - you could expect to be in the same condition in the afterlife as your corpse is in the living world. Think about it for a few moments.
At least symbolic animal sacrifices made of clay could be expected to count. I'd have looked forward to having a whole herd of goats to milk whenever after struggling with no livestock, hey?
Even at the pharaoh level, the image of the afterlife wasn't quite unified, let alone static.
Many mythologies have one or several deities occupied with creating intricate traps and riddles in order to "test" humans. The only problem is that many to most of these tests could only be passed with Light-like levels of omniscience. Which is to say they are impossible, unless you have the Power of Plot on your side OR you don't actually solve it, but are ridiculously lucky.