William Osler's attributed assertion that "the good physician treats the disease; the great physician treats the patient who has the disease" captures an enduring tension in clinical practice: the distinction between addressing pathophysiology and attending to the person who embodies it. Despite widespread recognition that effective care requires understanding patients' life circumstances—their contexts—the implications of failing to do so remain understudied. Weiner and Schwartz's concept of "contextual errors" names a form of medical failure that occurs when clinicians overlook patient circumstances essential to appropriate care planning, even when their biomedical reasoning is sound. This article explores contextual errors as both ethical failures and practical obstacles to effective care, examining their cognitive origins, health equity implications, educational dimensions, and systemic enablers. Drawing on empirical evidence from unannounced standardized patient studies and real patient encounters, alongside theoretical insights from narrative medicine and virtue ethics, this analysis argues that contextualization represents not an adjunct to evidence-based medicine but its necessary corrective—the means by which medicine reclaims its human center.