Transactional Analysis (TA) is the main psychological underpinning we all use to help clients understand how their behaviour, thoughts and feelings are related. It also helps us encourage clients to move to healthier and more purposeful ways of operating.
This is something which is used time and again in coaching and beyond, and so I very much encourage the curious among you to read on and find out more about it and the man who came up with this theory, Dr Berne here