First, life is worthwhile if you learn. What you don't know will hurt you. You have to have learning to exist, let alone succeed. Life is worthwhile if you learn from your own experiences -- negative or positive. We learn to do it right by first sometimes doing it wrong. We call that a positive negative. We also learn from other people's experience, both positive and negative.
Second, life is worthwhile if you try. You can't just learn; now you have to try something to see if you can do it. Try to make a difference, try to make some progress, try to learn a new skill, try to learn a new sport. It doesn't mean you can do everything, but there are a lot of things you can do, if you just try. Try your best and go all out.
Third, life is worthwhile if you stay. You have to stay from spring until harvest. If you have signed up for the day or for the game or for the project -- see it through. Sometimes calamity comes and then it is worth wrapping it up. And that's the end, but just don't end in the middle. Maybe on the next project you pass, but on this one, if you signed up, see it through.
And lastly, life is worthwhile if you care. If you care at all you will get some results, if you care enough you can get incredible results. Care enough to make a difference. Care enough to turn somebody around. Care enough to start a new enterprise. Care enough to set some records. Care enough to win.