This is a debate that's been going on for centuries. People always appear to get very confused regarding the topic of what is "proper" use of a language. Basically, it all depends on what you want to use language for. If your primary purpose is social grooming (we human primates no longer pick lice & salt off each other; we mutter empty phrases at each other instead) then pretty much anything is fine. If we want to convey our membership of a particular group then we need to use the group's distinctive tropes ("it was like totally groovy, man, and like real far out"). If we want to communicate clearly then we need to utilize adequate grammar and a lexicon that is both precise and highly likely to be understood by our interlocutor. It's only when we get confused about these very different uses of language that we fall into expectation errors, or tangle ourselves up in transiently fashionable but intellectually vacuous ideas about whatever happens to be Politically Correct at any point in time.