Resistance can be conscious or unconscious. As with most defenses, the unconscious parts are the most limiting; mostly because we don’t know about them. Consciously we think we are opposing something on the outside, when in reality we are defending from knowing something on the inside. That is why the real frontier is within us.
Resistance is costly for at least two reasons: first, it detracts from energy that you could direct toward excellence—it requires energy to keep something hidden from yourself—and second, it restricts the range of thoughts and emotions that others feel comfortable sharing with you—even unconsciously—and thus the talents they will willingly apply to their work.