Your self-image is not a mirror. It is a portrait, painted at some point in the past, mostly by other people, and then hung permanently in the hallway.
It gets formed early and it gets formed carelessly. A teacher's remark. A comparison with a sibling. A period of being excluded at thirteen. None of these were intended as permanent assessments. All of them frequently become one.
What makes self-image so durable is that it is self-confirming. If you believe you are not good in groups, you will enter groups braced and watchful, which makes you stiff, which makes the interaction awkward, which confirms the belief. The evidence is real. The causation runs the wrong way.
In coaching, the interesting question is never is this true. It is when did this get decided, by whom, and on what evidence — and does that evidence still exist?
The answers are often startling to the client. A senior professional discovers that their conviction that they are fundamentally disorganised rests entirely on a school report from when they were eleven. Twenty-five years of contrary evidence has been quietly filed as exceptions.
Updating a self-image is not affirmation, which mostly does not work because you do not believe it. It is evidence collection, done deliberately, in the face of a filter designed to discard it. It is noticing the disconfirming instance and writing it down before it evaporates.
That is slow work. It is also, in my experience, the single change that produces the widest effects across a person's life — because you cannot behave for very long in a way that contradicts who you believe you are.