To add onto PeeJay, he is saying that psychotherapy that only focuses on what happens around you (the "A" or action), or therapy that only focuses on your response (the "C" or consequence) isn't as effective or as good at helping you. True psychotherapy should focus on your beliefs and interpretations of situations (the "B" or between).

For example:
You're 24. Your mother calls you and yells at you about wrecking your car (A). You feel angry as a result (C). You feel angry because it was an accident and you are an adult who should not be yelled at by your mother, and you also hate how much control she tries to have in your life (B).

Therapies can focus on:
- A: Your mother yelled at you. So in order to make sure that doesn't happen again, maybe you could cut ties with her. Problem solved.
- C: Try to find a way to tolerate her yelling and calm yourself down so that it doesn't make you angry anymore. Maybe venting to a friend, going for a walk, or writing about it, or even yelling back. Problem solved because she doesn't bother you anymore.
- B: Spend time figuring out why she bothers you so much, and uncover the fact that she has always been controlling and blaming. Work on the beliefs and thoughts activated by that and similar situations to reduce future response to similar situations.