People are fascinating. When I was in an executive role, I loved interviewing people, even when they were clearly a terrible fit for the job/company. I take every opportunity to meet and listen to interesting people. I have found one question to be incredibly instructive, whether used in an interview setting or a personal one...
To date, what have you wasted the most time doing, and what do you wish you had spent that time on?
In an interview, it shows self-awareness and an ability to adapt and grow. A good answer to this question usually shows that you are talking to an ambitious person and a lifetime learner. There's a clear element of humility, as well.
In a social setting, this question gives you an opportunity to learn a tremendous amount about the path a person has taken. If you admire this person, pay special attention to their answer.
Now, take a minute for yourself and look back. Where have you wasted the most time? What do you wish you'd been doing? You are about to give yourself some great advice.
For me, for too long, I spent my energy going too wide with too many people/projects. I am a people-pleaser, and I still do not always use wisely enough the power of 'no.' I wish I had focused on going deeper with a few. I try to do it a little better every year.
Have a great weekend. What'd I miss?