Cognitive Behavioral Therapy, or CBT, as it is often called, is a very popular and effective kind of counseling / psychotherapy. The core idea of CBT is that, generally, our beliefs determine the effect that events have on us.
Now, obviously, there are some events and some effects that have nothing to do with our beliefs. Getting hit by a bus will probably hurt your body, regardless of what you believe about physics and automotive technology. Similarly, losing an important relationship will probably cause you emotional pain, because emotional attachment operates on a level deeper than our cognitive awareness. But in both cases (assuming you survive the bus, of course) your beliefs will likely have a lot to do with your recovery from the event.
Imagine, for a moment, if a close friend or a romantic partner were to unexpectedly end your relationship. Hurt, loss, and confusion would all be normal things to feel. But how strongly you feel them, how long you feel them, and how you feel about relationships in the future, would have a lot to do with what you already believed about the relationship and about yourself. The break up will probably hit you harder if you believe that being single means being a loser, than if you believe your personal value does not depend on whether you are in a romantic relationship.
CBT helps us find the untrue and unhealthy beliefs that are contributing to the problems in our lives. It helps us test and challenge those beliefs, and ultimately replace those beliefs with ones that are healthier and more helpful to us. The first step in CBT — and a practice that you can start now — is to simply pay more attention to the beliefs, judgments, or evaluations that you make throughout the day, often without realizing it.
For example, maybe you make a mistake at work, and think, “I’m never going to be good at this.” When you notice this thought, ask yourself, “Wait, is that actually true?” “Why do I believe that?” “Does believing that help me or hurt me?” “Is there some other possible belief that would be more helpful to me?”
There is a great deal more to Cognitive Behavioral Therapy than what I have described, here. And if you have a significant emotional or mental concern that could benefit from treatment with CBT, I encourage you work with a counselor or other qualified professional. But making a practice of watching for and challenging unhealthy and unhelpful beliefs is a good practice for anyone who wants to be happier and more effective.