What would you say was the best thing about stories? The happy ever after/for now ending? The twist? The engaging characters?
Any decent story, to my mind, has to have at least some of those elements but, for me, the best stories reveal something about human nature that, for whatever reason, has not occurred to me before.
A good story will show you something about yourself and challenge you to think about whether you would have done what Character X did or not. A good story also shows consequences from action and, sometimes, inaction. You should be asking yourself what would I have done had I been the character in this story?
Do you find yourself a bit less quick to condemn when doing this? Putting yourself in the shoes of characters, whether you write them or not, can be enlightening.
I also love it when justice is seen to be done where the story calls for it given we all know that so often doesn't happen in life. This is one reason for the continuing huge popularity of fairytales.
And you can't beat pure escapism as one of the great joys of story reading and writing. So whatever the best thing for stories is for you, enjoy it all!