The term “extravagance” has long been a versatile descriptor in literature, employed to capture a spectrum of excesses—whether in behavior, expenditure, or even thought. In certain contexts it criticizes the wasteful pursuit of luxury or ostentation, as in Stendhal’s remark contrasting appearances with better examples ([1]) and Dickens’ admonition against ruinous profligacy ([2]). At times, it pinpoints the unchecked fervor of ideals and passions, seen when authors explore the wild extravagance of creative or emotional expression ([3], [4]). Other writers use the term to comment on societal or moral failings, contrasting sensibility with impulsive indulgence, as exemplified in the measured observations by Emily Post ([5], [6]) and Confucius’ caution against excess ([7]). Across these examples—from lavish displays of dress and finances ([8], [9]) to the overreaching ambitions in public life ([10], [11])—“extravagance” emerges as a critical lens through which authors examine the balance between restraint and excess in human affairs.