The Psycho-Cybernetics classic by Dr Maxwell Maltz is not just about the operating  mechanics and the significant impact of self-imge psychology and the goal striving mechanism.

It also touches on the imperativeness and urgency of developing opportunity sensitivity mindset, as exemplied in these astute observations of the author:

“What is opportunity, and when does it knock? It never knocks. You can wait a whole lifetime, listening, hoping, and you will hear no knocking. None at all. You are opportunity, and you must knock on the door leading to your destiny. You prepare yourself to recognize opportunity, to pursue and seize opportunity as you develop the strength of your personality, and build a self-image with which you are able to live - with your self-respect alive and growing.”

“Live in the present. The past is gone; the future is unknown – but the present is real, and your opportunities are now. You must see these opportunities; they must be real for you.

The catch is that they can't seem real if your mind is buried in past failures, if you keep reliving old mistakes, old guilts, old tragedies. Fight your way above the many inevitable Traumatizations of your ego, escape damnation by the past, and look to the opportunities of the present.

I don't mean some vague moment in the present – next week or next month, perhaps. I mean today, this minute.”