Great stuff! I would like to add on for point #6 - choose your hardship.
Yes, everything has a law of natural growth, but if one spend too much time sharpening a skill and still enjoy little success, it's probably better to just focus the time and energy on sharpening something else.
John Maxwell once told me that if he scores himself 2 out of 10 at singing, and goes for singing practice all the time, he will only grow by 2 points in 2 years, making it 4/10. Hobby is fine, but no one wants to pay for average.
However, if you are already 7/10 at public speaking, and spend 2 years to push it up to 9/10, people would queue up to hear a 9/10 speaker.
RE: Top 10 insightful life lessons in 2017