Confession: Whenever I hear an American say "an historic...", pronouncing the "h", I roll my eyes at the pretense. That's the only word I think I've ever heard someone swap in "an" for "a" before a pronounced consonant.

Now, if they used the British-style "an 'istoric event", that's fine. In American we don't pronounce the "h" in "herb", so someone here saying "an herb garden" would follow the rule correctly and sound normal.

But "history" with the full "h"? To me it screams "this person memorizes without understanding", or at least "this person desperately wants to sound posh but fails". It's the verbal equivalent of wearing a polo shirt with a giant logo, imagining if a tiny one is fancy, then an enormous one must surely be exactly what rich people would wear.