I think one of the toughest things in life is to avoid becoming cynical, period.
You're in a work-place where you feel like you're always walking on egg shells. The house is always a mess; there's always something to clean. The dog wants to go for a walk, every ten minutes. stress levels sky rocket and you can never please everyone- ever.
Recently, I've learned that if you're pissed at somebody, the best way to cope with it is to just flat out tell them. Holding it in is painful and whether they react the way you want or the way you don't, it feels a hell of a lot better afterwords. This works at work (granted you don't get fired, and I thought I might this past week) and it works in any other relationship in your life.
If the people you confront care about you at all, your words will mean something to them and they'll respond, directly or indirectly. Sometimes you've got to let the emotion spill over, anger, tears, and everything in between.
It's hard, I know, but putting down the pounds and pounds you've been lugging around over time feels good, and you'll sleep a lot easier after. Again, trust me on this. I know first hand.
On the other hand, if the people you confront don't care and don't respond, forget about them. That's a place, a job, or a relationship that you don't need. I totally life by the motto surround yourself with those who bring you higher and if certain people in your life don't, then you don't want them in it.
I had about one hour of sleep last night, yet for some reason, after over two months of feeling angry and being cynical, I was excited to go to work today. I was tired as hell, but I still felt incredibly great after my last weeks confrontations, and work went well in my mind, whether things changed or they didn't.
Life is what you make it. If you view it as bad, too hard, depressing, or just plain crappy, that's how it will be. There's always something to look forward to. There's good in so many people, and that is enough to keep me going.
Conclusively, you've just got to let certain things go. You can't please everyone. If you try to, you'll live in pain, twisting and turning with every night's unsuccessful attempt to fall asleep. Sometimes one night of one stress-free hour of sleep is worth more than one night of eight hours of tossing and turning. Believe it.