"The most valuable habit I've acquired is using pain to trigger quality reflections. If you can acquire this habit yourself, you will learn what causes your pain and what you can do about it, and it will have an enormous impact on your effectiveness."
-- Ray Dalio, Principles: Life and Work
Reading Dalio compounded my habit of self-reflection and learning. If you look back a year and can't think of one thing that you've fundamentally changed or learned... then you're probably moving backwards.
What is the most important thing you have learned or changed in the past year? This can be in any aspect of life: relationships, career, human nature, etc.