Happiness is simply a state of mind in which our thinking is pleasant a good share of the time.
You make mistakes. Mistakes don't make you.
Every day you must try to make your own self-image grow; this you can do.
Ignore past failures and forge ahead.
A step in the wrong direction is better than staying on the spot all our life. Once you're moving forward you can correct your course as you go. Your automatic guidance system cannot guide you when you're standing still.
It is well known that when Thomas A. Eddison was stymied by a problem, he would lie down and take a short nap.