Okay, just to clarify, when I said optimistic, I didn't mean the sort of "everything is always going to turn out alright" kind of things. Not even MLP is like that; I'm pretty sure one of the things Faust mentioned in an article somewhere was how much it bugged her that everyone always became friends in the end, because things don't work like that.
What I meant was that I enjoy having a show that doesn't take place in a world where everyone is a jerk or an idiot. Those people exist, but they can be dealt with. And I honestly think it's kinda important that some of the antagonists
aren't shown turning good in the end; as noted, the world doesn't look that way. (I'm not trying to start up another morality debate about Gilda and Trixie, I'm just pointing out that within their episodes, they didn't befriend the mane cast) I think it's good that the show manages to balance it's "try to be understanding and nice to people" with "even if you're nice to them, some people will still be jerks anyway".
As Kegisak mentioned, the show doesn't have any complete monsters, but that's okay not everyone encounters them. The show focuses on everyday-type interactions with jerks, and teaches kids how to deal with that, which is a billion times more practical that either "the world is a
Suger Bowl" or "the world is a
Crapsack World".
In short, I like the fact that it portrays a world where people have their flaws, but those flaws can be worked through.