It’s up to us to determine our happiness. No one else is in charge. No one else is to blame. No one else gets the credit. Our happiness is tied to our willingness to be responsible for our own moods. That’s a certainty — one of few in this life. It’s also a certainty that any happiness we feel in the company of others is not the result of their attention, their happiness or good fortune, or their commitment to us. It’s the result of our commitment to ourselves. Let’s be grateful for that! Accepting this, accepting that we are responsible for ourselves and ourselves alone, is the key to allowing the rest of our lives to unfold as they were meant to do.
— Karen Casey, Change Your Mind and Your Life Will Follow, p. 51