I was a copy editor, so of course I had to be aware of grammar, and I was very good at it. A few things I learned:
Even experts disagree about what is correct.
Style guides and other arbiters are all correct within certain contexts. For example, one style might be appropriate for a business memo and another for a novel.
Not everyone is good at grammar or spelling. You have to ask yourself how important it really is. Do you want to hate on someone over something like that? How about people who aren’t good at sports? Who don’t know how to dress well or prune a fruit tree?
Although I had a specialized skill that was of value in a certain industry, in everyday life I really don’t care how people express themselves.