I suffer from depression, so this thread fails in my mind, when I occasionally do feel happy, I don't trust the emotion, like it's fake, or about to be ripped away...
However, my cat has been very ill suffering from mini-strokes, no not petting, but 'strokes' - paralysis of one side of the body, she's ok now and when I am in the house she never leaves my side, she's even started speaking again which is something she hasn't done since she was a kitten. For all that fucking shit I have to put up with, all the idiots, all the blatant stupidity and greed that the human race shows me, the furball by my side depends on me and a small feeling of private happiness grows.