I say hiss-storic but have always used "an" as the sound still fits the aural pattern rule in my head. It never even occurred to me that people would ever think

I say hiss-storic but have always used "an" as the sound still fits the aural pattern rule in my head. It never even occurred to me that people would ever think it was wrong or pretentious to use "an". Though, I was always conscious that "a historic" wasn't wrong, either; yet it still looks and sounds off to me, like someone is deliberately exaggerating a hard h sound.