Americans in the late nineteenth and early twentieth centuries took the whole idea of fashion pretty damn seriously. People were expected to dress in a fairly formal manner, even when it did not make a damn bit of sense to do so. A good example of this would be many farmers and other workmen wearing ties while doing jobs where having a long piece of cloth hanging from your neck isn't really the best of ideas. There were also all sorts of strange rules, that everybody followed for some mysterious reason, about when and where one could wear didn't types of clothing, the most famous being not wearing white after Labor Day. However, probably none of these stupid rules caused quite as many problems as the ones regarding the wearing of straw hats.
At the time, hats were a fashion necessity for all men, with felt hats seen as the acceptable norm for the discerning gentleman. There was just one problem. Felt hats were hot as hell during the summer, by which I mean wearing them was about the most miserable thing you could do outside of shutting your dick in a door. Due to this rather unpleasant shortfall, starting in the 1890's straw boater hats began to gain popularity for summer wear. Boater hats are of course those wide brimmed flat top hats you always saw dandy's from back east wearing in old westerns. You know, the hats barbershop quarters wear. Anyways, at first resisted as being uncouth, people eventually gave in to the notion that maybe it would be better to wear a something at least a little more comfortable during the summer months and straw hats became acceptable attire, within limitations.
As straw hats became popular, so did an unwritten rule on when it was acceptable to wear them. Though there was never any super secret fashion committee making such decisions, somehow it became standard practice for it to only be okay to wear straw hats between May 15 and September 15. As with any societal norm, anybody caught wearing a straw hat after September 15, creatively called Straw Hat Day, would face widespread public ridicule. However, over time this public ridicule shifted into it becoming socially acceptable for youths to knock the straw hat off of any offenders head and then stomp said hat into oblivion. Rather than try to curtail such acts, society as a whole instead accepted it as a wonderful American tradition, with newspapers even warning of the impending approach of Straw Hat Day.
This was the state of affairs in 1922 when a group of young men in New York City, unable to hold back their excitement, decided to get an early jump on the festivities by going after straw hats two days early. Unsurprisingly, things got out of hand when the youths tried to stomp the hats of a group of dockworkers, who being dockworkers, decided to solve the problem with their fists. A brawl broke out which quickly spread, even stopping traffic on the Manhattan Bridge for a time before the police broke everything up. Young men reading about the brawl in the newspaper the next day thought it sounded pretty fucking awesome, and before days end a mob of around 1,000 people, some armed with large sticks with nails driven through them, were roaming the streets, stomping hats, and beating the crap out of random people. As with most things of such nature, the mob quickly devolved into a riot which lasted eight days before the police could get it under control.
Now one would think that such shenanigans would put a stop to the whole hat smashing tradition, but one would be wrong. Straw Hat Day continued for years afterwards, with similar, albeit smaller, riots breaking out from time to time. In 1924 one man was even murdered for wearing a straw hat. In the end the tradition died out by the 1930's as boaters dropped out of fashion to be replaced by straw Panama hats, which looked enough like the popular felt fedoras of the day that society collectively decided that people could wear whatever hats they wanted regardless of the time of year.