When one person does it, it’s an expression of one’s individuality, a fashion statement, etc.
However, when everyone does it — or at least the male of the species — it instead becomes something else entirely: a de facto uniform. An act of conformity. A cliche.
What am I talking about?
The requirement, apparently, that every guy in Chicago between the ages of 15 and 75 goes around wearing a baseball cap.
(And no, if you’re bald and have a paunch, simply wearing a baseball cap doesn’t suddenly make you young and hip.)