My main example is How can I evaluate $\lim_{n\rightarrow\infty} \frac{n\cdot 2^n }{3^n}$? with Improving answer about evaluation of $\lim_{n\rightarrow\infty} \frac{n\cdot 2^n }{3^n}$ as a related issue.
I have no problem with the robust debate over site protocols. And I think we all want to help the people who post questions on the site to post good questions.
As the site develops, many common questions have answers or near answers, and the curation of this may become an issue.
I also appreciate that I am not a professional mathematician, though some years ago that was a viable life path, and people I knew, or whose names I recognise, are making phenomenal contributions both to mathematics and to the site. My goal for being here differs a bit from the goal of the site. I enjoy maths and want to help others to learn to enjoy as well. The site is for good questions and good answers. There is a substantial overlap, but where I am on the wrong side of things, I don't mind being told off, down voted etc. I've never been part of a good mathematical community where debate was not robust.
But I do question how robust debate amongst regulars might be off-putting to people who are dipping their toes in the water of the site. The person who posted the question referenced above might be rather bemused at the response. As I noted in my comment on the question, the best reason for closing is a really helpful duplicate.
So how do we best conduct robust debate without accidentally personalising it in an unhelpful way?