Recent poor English from natives

I know that both British and American speakers of English use sloppy  and incorrect language regularly, but here are two examples unique to US English that I have been hearing more and more recently. I wonder if they may become accepted as standard someday. I hope not, as they really are lazy, and to say them correctly doesn’t require any thought.

1) “If I would have known about the party, I would have gone to it.”

We shouldn’t use “would have” twice. I suppose people get it confused with “If you would…” sentences. The correct pattern is as follows: “If I had known about the party, I would have gone to it.”

Therefore, they also make the same mistake with “I wish”. For example, “I wish you would have told me about it,” instead of the correct, “I wish you had told me about it.”

2) Americans don’t seem to like the lack of clarity in the use of “you” for both singular and plural. So, instead of “you” for plural they say “you guys”. Well, that’s OK for casual situations. But… instead of saying “Your desserts will be coming soon,” some people say the incorrect “You guys’s desserts will be coming soon, ” or even the unforgivable “Your guys’s desserts. ” The most recent example I heard was, “I’d like to hear your guys’s opinions on this.”