“The control center of your life is your attitude.”

1950s, Loving Your Enemies (November 1957)
Context: There is something within all of us that causes us to cry out with Ovid, the Latin poet, "I see and approve the better things of life, but the evil things I do." There is something within all of us that causes us to cry out with Plato that the human personality is like a charioteer with two headstrong horses, each wanting to go in different directions. There is something within each of us that causes us to cry out with Goethe, "There is enough stuff in me to make both a gentleman and a rogue." There is something within each of us that causes us to cry out with Apostle Paul, "I see and approve the better things of life, but the evil things I do." So somehow the "isness" of our present nature is out of harmony with the eternal "oughtness" that forever confronts us. And this simply means this: That within the best of us, there is some evil, and within the worst of us, there is some good. When we come to see this, we take a different attitude toward individuals. The person who hates you most has some good in him; even the nation that hates you most has some good in it; even the race that hates you most has some good in it. And when you come to the point that you look in the face of every man and see deep down within him what religion calls "the image of God," you begin to love him in spite of. No matter what he does, you see God’s image there. There is an element of goodness that he can never sluff off. Discover the element of good in your enemy. And as you seek to hate him, find the center of goodness and place your attention there and you will take a new attitude.

Source: The Authoritative Calvin and Hobbes: A Calvin and Hobbes Treasury

1950s, Conquering Self-centeredness (1957)

Zig Ziglar
200 Motivational and inspirational Quotes That Will Inspire Your Success
Variant: Your attitude determines your altitude. - Zig Ziglar