My worst is 'Lessons will / have be / been learned ...' usually when a loss of life is involved.
My other one is 'With respect ...' which you know heralds a sentence concerning anything but, and the more exaggerated it is - using with word 'greatest', that means complete contempt is about to flow your way.
The other prefaces that mean the opposite are phrases like 'I'm not being funny but ...' Yes you are!, or 'I'm not racist but ...' - see previous.
In writing - and I have pointed it out on this site, the simple preface of 'So ...' often indicates that the following will be proof that the writer either didn't read what they are replying to, or if they did, they are deliberately, or out of ignorance, completely misunderstanding the sense of it.