I love my life. I'm content. Happiness is a feeling I get sometimes when I think about it, or something nice happens that reminds me of what I have or did.
It's not a strong emotion I used to feel when I was a kid, but things were like a roller coaster back then. Now when things aren't perfect, I can still enjoy the ride.
I know shit happens and there are people in situations that make it difficult for them to be happy, but I don't really get the people who complain about the stupidest stuff. I believe that they must actually be spoiled or never experienced much, and they just take their lives for granted. That surely doesn't get anyone anywhere.
I came from a position where nice things were never a given, so I was sometimes forced to make the best out of every situation not to get back into depression, and it sort of stuck. That and learning to live in the moment actually helped me get a lot of nice things done, and the fact that I managed to do more than I thought I would at this point makes me feel happier, so it's been a self-reinforcing cycle ever since.
I go to sleep every night feeling happy, even when things aren't perfect or something hurts, I just appreciate my life. So yeah, I am very happy with my life.
Not sure why you would feel guilty about feeling that way too. Being happy with your life is not selfish, quite the opposite, as it only affects others around you positively. Surely being around people who were happy with their own lives, regardless of their circumstances, only made me appreciate more things. A couple of years ago I met a great friend at work. Last year he died of lung cancer. He was the most positive person I knew. He would never complain about a thing and the problems were just like ammo for him to make new jokes about. Objectively, he had lots of problems, but it never felt like any of them actually affected him, and I'm sure that he died happy. Just a few days before his final day, when he was already unable to speak or breath by himself, he would text me to cheer up because he's had a great life, and I better be in my A-game during his last days because a gloomy face won't give him extra days to live, and that we should enjoy and talk about the good days when he's still there to reminisce. Everyone loved him for his attitude, he affected a lot of people positively, I learned a lot from him and will always remember him very fondly.