Faces at coffee shops

Something about drawing faces in coffee shops. Public sketching becoming more popular with more retirees? Voyeuristic? In the spirit of Daumier and Toulouse laTrec and fair caricature artists everywhere. Look for the essence of the person in their outward appearance? Perhaps, but what do I know from glancing at a face from across a room? Sargent quote about "capturing the inner soul of a person..."