> Not caring about what other people think is truly freeing.

1. young people worry about what others think of them

2. middle age people stop caring what others think of them

3. old people realize that nobody is thinking of them

But #3 is a reality that slowly blossoms, not something you're born into as a young person. We are also all judging each other to different degrees, and some of these judgments do matter.

I feel like the advice "stop caring about what people think" is pretty useless for a lot of people.

Really, how much you care about what other people think depends on what phase of life you're in. In your adolescence, your social survival and who you get to date largely depends on the opinions of others.

When you hit your 30s, usually you have your own family and your own tribe, and other people just don't matter so much. You're in a different phase of life with different goals.

I guess it's possible to find a way to not care what people think in your 20s, too, but for those who DO care a lot, telling them not to care isn't helpful.

Giving advice to others is rarely helpful, even if it is excellent advice.

Depends on the audience. "Not caring about what other people think" may (but usually isn't) helpful advice to -most- pro musicians/composers... or other creatives hoping to land and retain an audience.

You have also made an important point, equal to Feynman's.