I think it helps to be tuned into the idea that when you really get down to it, the world is mostly quite terrible to put up with. The only things that really get most of us through just being faced with that reality are the little things, to use a corny cliche, that make it all worthwhile. And above all else, to me, to have a good sense of humor to laugh off most of it. Even if that laughter is a little inappropriate. If it helps you process the terrible, then it's done the job it was supposed to do.
I think it's important to keep this in mind with your characters and whatever they have to go through.
In fact, Woody Allen summed it up beautifully in "Anne Hall."
"Life is full of misery, suffering and loneliness, and it's all over much too soon."
It might not be a bad idea to think of this concept and have your characters try to express that through their own words and actions.