We learned many defense mechanisms at an early age, thinking that a good defense would be the best protection. We have continued this approach as adults. We're still afraid that we'll be criticized or we'll fail if we don't assert ourselves. On some level we worry that we won't be functional if we aren't assertive. We might never leave the house if we don't pump ourselves up. Perhaps we should reexamine these assumptions, to see what really works. We need to investigate whether it's beneficial to build ourselves up, especially to do so by putting others down.
"Discovering Our Capacity to Love," in Mindfulness in Action
by Chögyam Trungpa Rinpoche, pages 9 to 10.