Maybe this isn’t the answer you’re looking for: my job is my passion and the idea of retiring sounds horrible. I image it will only happen when I’m too senile to keep doing what I love, and that’s clearly not something to look forward to. But who knows… I know old people who are tired and just want to rest.
(I got lucky, since I happened to be passionate about computer programming. I know most other people don’t have the same option.)