What happened on this date? And why would I care about it enough to post about it?
Well, it's the day that JFK was inaugurated president of the USA.
He had the distinction of being the first president to NOT wear a hat at his inauguration.
At that moment, one could no longer make the argument that wearing a hat is the social convention for solemn events, becuase there's no event more solemn within American culture as the President on the day of his inauguration.
Until then, wearing a hat was within societal norms, was a perfectly conventional thing for men to do, and therefore was obligatory when Halakha mandated soelmn attire, such as on Shabbat and festivals, or a groom at his wedding.
After that date, there were two responses; one was to continue with the social conventions, which, at this point, no longer related to the hat as a norm. The other was to insist upon doing 'what has always been done', i.e., the hat had taken on a significance of its own regardless of the cultural context. At that point, hat-wearing became reactionary, and, as such, particulars such as color and style became more and more specific to the particular population who was perpetuating this style.
I, for one, tend toward the former approach, that one displays solemnity and respect by employing the conventions of the prevailing culture (like burping at the table in China, if that's what it takes), and not by reactionism.
I entitled this post 'A Black Day' simply as a pun, with no attempt to pass judgement on either the 'black-hat' phenomenon or the Kennedy administration.