Persistent self-criticism, impostor feelings, and chronic inadequacy are frequently reported in high-performing adults despite objective indicators of competence and achievement. Existing psychological literature has explained these experiences through constructs including perfectionism, contingent self-worth, self-discrepancy processes, and impostor phenomenon dynamics. Comparatively less attention has been given to the asymmetrical structure of evaluative access between self and other during self-assessment and social comparison. This conceptual paper proposes epistemic asymmetry as a contributing mechanism underlying persistent self-inadequacy in executive and high-performance coaching populations: the unequal access individuals possess to their own interior experience relative to the largely external and performative access they possess to others. High-performing individuals compare internally experienced doubt, contradiction, uncertainty, and emotional fluctuation against externally perceived competence, composure, and coherence in others. This asymmetry shares conceptual ground with established work on pluralistic ignorance and the illusion of transparency; its contribution here lies in extending that asymmetry into achievement-linked identity and executive composure norms, and in connecting it directly to the persistence of impostor feelings and contingent self-worth despite objective success. Particular attention is given to executive and high-performance contexts in which evaluative exposure, achievement orientation, and professional composure norms amplify these dynamics. Implications for coaching psychology and leadership development are discussed, alongside limitations and directions for future empirical research.