... So what happened? Why did guys stop wearing headgear in midcentury America? The turning point, most people say, was John F. Kennedy's inauguration. Before Kennedy, all presidents wore top hats on their first day at work. Kennedy brought one, but hardly ever put it on. Fashionistas say Kennedy, one of our most charismatic presidents, made hats un-happen. And, chronologically speaking, after JFK, guys everywhere, even balding ones like astronaut John Glenn, went topless. But I am the son of a hat designer. And my father, Allen S. Krulwich, had a different explanation. The president who de-hatted America, he thought,...