Why spend your life developing software unless you care about doing it well?
This quote was taken from a programming book, but it's larger than that. I dare say "caring about your craft" is essential anywhere. Why would you keep doing what you do instead of the thing you actually want to do?
The part about "doing it well" is a logical result of caring about your craft. When you do something you like, you'll do it well. Find something that gets you out of bed every morning, and the rest will follow suit.
If you don't believe me, believe Steve:
"You’ve got to find what you love. And that is as true for your work as it is for your lovers. Your work is going to fill a large part of your life, and the only way to be truly satisfied is to do what you believe is great work. And the only way to do great work is to love what you do. If you haven’t found it yet, keep looking. Don’t settle. As with all matters of the heart, you’ll know when you find it. And, like any great relationship, it just gets better and better as the years roll on. So keep looking until you find it. Don’t settle."
Steve Job's Commencement address, Stanford, 2005
Building software well serves multiple purposes. At first, it stands the test of time, because it is expandable. Second, it is easy to read, both for others and your future self. And third, it's just awesome to do. What gives more adrenaline than software that was built in a clever yet simple way? Nothing much, really.