Few people TRY to sound like a douche, after all, but "trying to sound cool" defines hipster douchery almost as well as the "fake culture" definition rt suggested. "Ya'll" does not sound cool in the South (nor, thanks to the Great Migration, most minority residents of Western and Northern cities,) it simply sounds far more natural than the deeply awkward "you guys." Likewise, in the Midwest and New England "you guys" is commonly a reflexive usage, while "ya'll" sounds forced, affected or both. Distinct singular and plural forms of the second person pronoun is generally desirable in any language, but since English abandoned that distinction nearly half a millennium ago, modern speakers are forced to improvise.

In line with that and the above discussion between rt and I, I wonder what (if anything) is English common second person plural outside the US.