I end all of my sentences with periods and I was told that I have a negative attitude at work because of it. Seriously, my manager's advice was to stop ending my sentences with periods.

I don't find this at all. There's a certain style, or flourish, to LLM-ish writing that makes it noticeable. It's not just spelling and grammar.

I have used em dashes and semicolons for decades. The LLM appropriation of my writing style has been almost as devastating as their impending vaporization of my career path.