"No one knows what they are doing" is basically always true.

Do not think this way if you are an electrician.

This was how I convinced myself not to drop out of engineering

This should not be a philosophy to live by if you're president of a superpower

Huh. Maybe I'll go into politics. 🤔

Try your hardest, but forgive your mistakes for the human error they are, and do try to keep it in mind for next time. The mantra is helpful for afterwards, when you notice all your various mistakes.

Make a bad enough mistake as an electrician and you won’t ever be making any more.

When I see what some of them make, they find ways to do things in a dumb way, trust me.

Nobody knows everything. So do your best educated guesses and act your best accordingly.

The best moment to apply that mantra is while you are still learning :D

And also when you are learning/practicing in a controlled/safe place :)