If I met a random person and they asked for my advice on how best to improve their lives, my answer would require almost no thought.
Although probably the thing that has the largest effect on someone's quality of life is their spouse, the direction of the effect could go either way, and I wouldn't wish the task of finding a good spouse on my worst enemy.
Similarly, telling someone to find a rewarding career or hobby is like telling them to find peace and happiness. It’s not terribly practical advice.
I might recommend taking a day or a weekend in solitude with the sole purpose of figuring out what they want to do with themselves, but I have not tried that myself, so I am unable to judge whether it is likely to produce any lasting benefits.
In comparison to finding a good spouse, finding a rewarding career, or taking an existential weekend retreat, my advice might sound trite, but I assure you, if my own life is any reasonable proxy for what can improve others' lives, then you ought to be listening carefully.
I would advise them to take up three things: (1) notebooking, (2) writing/blogging, and (3) self-tracking.
To me, these are not hobbies as much as routines you do for good health, rather like brushing your teeth. You could call it mental flossing, but I think it would be better described as existential flossing. Maybe a better description yet would be thinking.
Yes, thinking.
Notebooking is paying attention to and capturing fleeting thoughts and feelings; writing is developing and exploring those thoughts; blogging is sharing them and receiving feedback (which is a critical part of the thinking process, I'd say); and self-tracking is big-picture reflecting.
Simply put, if you are not doing these things, then you are probably not thinking well enough.
I won't bore you (or me) by weighing the costs and benefits of each -- if you are dying for explanations of their utility, I can try to dig up some well-articulated pieces -- I will just say that, together, these routines have made me considerably more self-aware, interested, and interesting. And more than any other activities, they have shaped who I am today.
You’d be hard-pressed to find a set of things with a higher return on investment because what else would produce significant benefits with such a minimal investment of time or money?
I wish I knew why more people don't do any one of these things, let alone all three. If you have ideas or theories, please share.
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If a random person came to me seeking advice who already blogs, notebooks, and self-tracks, I don't know what advice I would give them. That’s where I am in my life right now -- trying to find the next answer. (Again, if you have ideas, don't hold 'em back!)