On the Tim Ferriss podcast, Penn (from Penn and Teller) talked about the benefits of his extensive journaling practice (from the past 30-plus years). Every morning he writes a detailed report of the past 24-hours—who did he talk to, summaries of what he read or watched, etc.
After writing those, he goes back and reads the entries from 20, 10, 5 and 1-year ago, talking to his past self. He notices changes and patterns. For example, if he’s had the same argument with a romantic interest a year ago, he ends that relationship because things aren’t changing.
I recently found a journal from when I was 23 where I wrote that my career ambition was to help people find work-life balance. I don’t remember this at al. I so want to talk to that young, optimistic woman to tell her that dreams can come true.