Whatever it is that makes a person charming, it needs to remain a mystery ... once the charmer is aware of a mannerism or characteristic that others find charming, it ceases to be a mannerism and becomes an affectation.
Source: LA Herald-Examiner, 24 Jun 78
-- Rex Harrison, (Mar 5 1908-1990), English actor; His natural environment was theatrical light comedy in which elegance was preferred to depth, and urbanity to rough edges.