The Hidden Emotion Model is based on the idea that niceness is the cause of all anxiety. People who are prone to anxiety are nearly always people-pleasers who fear conflict and negative feelings like anger. When you feel upset, you sweep your problems under the rug because you don’t want to upset anyone. You do this so quickly and automatically that you’re not even aware you’re doing it. Then your negative feelings resurface in disguised form, as anxiety, worries, fears, or feelings of panic. When you expose the hidden feelings and solve the problem that’s bugging you, often your anxiety will disappear

David D. Burns (on of the people who popularized CBT) in "When Panic Attacks: The New, Drug-Free Anxiety Therapy That Can Change Your Life-Broadway"