Wait until you're 40! The things that are important to you will make themselves known. I'm 40 and have decided the things that matter are my family, writing, piano, taiji, and baking, in that order. A short list, but each one of those things could reward a lifetime of dedicated exploration, and each of them (okay maybe not baking) yields arbitrary philosophical depths. I need to spend time on other stuff, too, but I get that stuff out of the way as soon as I can.
"Upkeep tasks" are never worth making your main focus. Fooling with diets, the quantified life, exercise regimens... these are not worth making the focus of life. They make you healthy and functional -- for what? You need something to be healthy and functional for. Start with that thing (or things), and work backwards. You can't make oiling your wheels (or tending to your .emacs file) the whole point. And I don't mean we all need some all-fired existential purpose in life, I just mean we need something we've decided to do.
If you're not yet 40... uh... hang in there.
Sorry, this might be my first ever man-on-the-mountain, lemme-tell-you-how-things-are post, and I don't mean to make a habit of it. But I've got some years behind me, and a lot of mistakes, and this is something I feel pretty confident about.