It ebbs and flows for me, but I'll never get that excitement back from when I was a kid. I just have to get fulfillment from doing my job well, finding and creating an elegant solution to a stupid problem. Knowing I can do my job well helps a lot, especially when I compare what I offer to what my competitors sling out in the world. It's B2B software, so the bar is set very low as just about all B2B software is atrocious.

What also helps is having interests and hobbies that are in no way related to your job.