What matters most is having a mind that searches for what matters -- AT ALL.
-- Brandon Tart
If I were given the opportunity to talk with Confucius or any other ancient philosopher who asked that question, that is how I would answer it.
""A man at his maturity: when as a man he suddenly remembers the complete seriousness he had as a child - AT PLAY."
-- Friedrich Nietzsche
When I read the question, "what matters most?", immediately Nietzsche's maxim from Beyond Good and Evil came to mind. I love this quote because I suffer from being VERY serious almost all the time when in the company of others. In other words, I've needed to learn to "lighten up." We all need this, and when we consider what it means as adults to PLAY, we can remember the era of our innocence when all we ever planned regarding tomorrow, was that we would repeat the very actions of the present, after we awake from our dreams of flight!
To, and for all of us, I would say that it is good to remember to take time as an adult to play. By play, I mean that we should pretend, imagine and daydream. This gets tough for adults. Maybe writers and artists are naturally inclined, but artists do often get themselves tangled up in "hip" actions, becoming overtly concerned with trying to save the world - there is time for that - but how are any of us going to save the world if we can' resemble, on some level, who we were when we were innocent children?
There are so many things that I believe we worry about simply because we've been socially engendered to focus on them. Careers, mortgages, cars, degrees and such as these are modern inventions, which, if one pays careful attention to history, have not always been the focal point of mankind.
Of all of these, we are forced to consider where family, love, religion and time for life fits into these. Careful observation tells us that they all "matter." We can consider all that bombards those things which we are certain "matter most," so I am compelled to say that the only definitive means to determine what matters, is to draw the line, stand one's ground and say with a holy roar to the status quo:
"I have set forth to determine what matters most, and we MATURE MEN have gained little ground for having forgotten to take aim and fire at those things that don't matter -- AT ALL!"