Serifs are the little lines trailing from the edges of letter and symbols. (Sans-serif type, on the other hand, doesn't have them.) He likes ribbon cloth lanyards because, he says, they feel rich.
Given a lens to notice lettering styles by the typographer Paul Shaw, I counted six distinct serifed fonts in the lobby of the building where I work, punctuated by only one word -- EXIT -- entirely without serifs.
With one slight exception, perhaps of at least curiosity interest to Mathematica aficionados: he suggested that cells in Mathematica notebook documents (now CDFs) should be indicated not by simple vertical lines but instead by brackets with little serifs at their ends.