Understanding the Irony Gap

I think it just gets down to experience at school, and subsequent norms of acceptability in social intercourse. One of the reasons Americans don't see it when Brits are being ironic, is because Americans simply will not believe that anyone is so unkind and so socially shriveled that they would casually use deadpan cruelty and nastiness on a perfect stranger for the sake of "a laugh". So an American must interpret an interaction like that as straight, rather than ironic, otherwise they would have to, by their own lights, believe something reprehensible about Britons. In general, Americans simply don't get the idea of cruelty without anomie.

This is part of why I say that Americans are dogs, and Britons are cats.