Love what you do
Pete's pointed to this lovely quote: "If you enjoy programming computers, count your blessings: you are in a very fortunate minority of people who can make a great living doing work they enjoy. Most people aren’t so lucky. The very idea that you can “love your job” is a modern concept. Work is supposed to be something unpleasant you do to get money to do the things you actually like doing, when you’re 65 and can finally retire, if you can afford it, and if you’re not too old and infirm to do those things, and if those things don’t require reliable knees, good eyes, and the ability to walk twenty feet without being out of breath, etc."
Personal anecdote: when I was 19 I spent a summer working in the refrigerated cold-store of a dairy, pushing trolleys of milk around from 8am and 6am. It was OK - I got reasonably fit over the course of the summer and it gave me some spending money and something to do.
But there were a couple of old guys there who'd been there 30+ years, doing this every day... and from talking to them, it wasn't something which got them fired up, just a necessary means to support themselves.
Getting paid for doing something you enjoy is a massive privilege.