Playing an instrument
Really?
strongly disagree with "learning an instrument". I wasted lots of time on that. The costs are high, and all the benefits are either dubious or can be more cheaply obtained through other means.
At least for classical instruments, getting good enough to not embarrass yourself is quite expensive, both monetarily (equipment, teachers) and in terms of time. At >1k hours of practice and ~$10k invested, I'm just barely good enough to get paying gigs (which I'd lose in a second if the people paying me knew anyone who'd attended conservatory).
How is playing an instrument a big win, and how is it not much effort? (I'm assuming it involves not learning a classical instrument.)
Playing the piano or guitar, even at a semi-beginner level, can be a lot of fun. You won't make money off of it, but you can show off to friends and family members. It's like playing tennis or basketball: you need a high level of skill to compete seriously, but you don't need to be even as good as the local high school team to have fun with your friends.
Incidentally, I think it might be easier to achieve minimal competence on a guitar than on many other instruments - you can perform a lot of songs just by learning a few chords and singing the melody.
This is the question asked by John Cook on Twitter. He lists responses from different people:
Mine are: quantum mechanics, Python, cooking, the language of philosophy.
What learning curve do you wish you'd climbed sooner? Give reasons and stories if you feel like it. Do you think other people should climb the same curves?