Proms are strange creatures.
We didn't have them here in my time as a student, but US culture penetrates fast. Now several high schools do. I guess we're just entering the stone age
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Still no prom queen or king, though, thankfully. No valedictorian, salutatorian or any other pig-latinorian.
This brings the attention to 2 of the US cultural features.
One is voting. In the US, you don't only vote for the student council, like elsewhere. You vote for who's the brightest, the prettiest, the most likely to succeed, etcetera.
The other one is competition. From the very start they compete for everything: grades, popularity, a place in the cheerleading squad.
The day I learned there were extreme differences between American and British cultures was on Christmas '75. I was among the guests of a professor of the London School of Oriental Studies. There were Brits, Chinese, Japanese, one Mexican (me) and an American woman from Sacramento. We played movie charade. Towards the end, the Britons were quite angered by the Sacramento girl's behaviour: she wanted badly to win at the movie charade game, and it showed. Honestly, I hadn't noticed.