The ideal level of confidence is slightly beyond your actual ability.
Never be so detached from reality that you become delusional, but never dip low enough that you become your own bottleneck.
Most people are capable of more than they believe.
The modern mental illness is anxiety.
The symptom is inability to fall asleep.
The evidence is pills, meditation apps, opioids, and sleep trackers.
The causes are oversocialization and overstimulation.
"If you look for truth, you may find comfort in the end: if you look for comfort you will not get either comfort or truth--only soft soap and wishful thinking to begin with and, in the end, despair." CS Lewis
You can always find someone to talk you out of your own best ideas.
Feedback has value, but don’t use it as an excuse for stasis.
Do what you know needs doing.
Make yourself oblivious to irrelevant opinions.
Act.