For me the thing that makes my life worth living the most is my daughter. Anytime I'm down, not believing in myself, in people, in the world in general, she's got a magic touch that makes it all full of sense again. The combination of this huge responsibility and the powerful bond between parent and child slaps me in the face saying "Man the fuck up, you've still got a job to do". It helps.
Other than that, I think it's passion. Personally I'm into making music and DJing, so anytime I need to relax and separate myself from this world, I put on my headphones and surround myself with my favourite soundscapes, beats and rhythms. Or when I'm at the club, behind the turntables and I see the crowd reacting to the music I play, people with their eyes closed, smiling gently, all moving to the same rhythm... it all makes me feel like I'm in the center of the universe and is the most pleasant and fulfilling emotion/feeling/experience I've ever had in my life.
And lastly, moments. There are episodes when I might think that my life is complicated or simply shit, but then I realise that it's not all like that. There are still moments that are good, inspiring or uplifting. So everytime I drive my car to work in the morning and the sun is shining, the trees blossom all around me - I'm grateful for the sun and the trees. Or maybe it's raining or snowing, but it's a day when I feel healthy - I am grateful for this too. Or maybe I feel compassionate for someone and try to brighten up their day with at least a smile - like the lady at the mall, working at the check-out till 10PM for minimum wage. Little things add up...and they make big things.