This is the most important idea to work on. How we see ourselves, and work through difficulties in our lives, sets up the pattern for what we do in the world.
We forget that others are unaware of our internal world and the thoughts that circle round our heads. We are judged solely on our external behaviour. Therefore, if we choose to limit what we do this will be picked up by others and interpreted. We might be seen, perhaps, as someone who is not capable or ambitious and so less is expected of us and this can lead to feeling underestimated.