Although I push for a lot of upfront agreement, most of the back and forth arises from little things, like a variable name being too long, a newline between struct members, or a docstring that could be removed because the code is expressive enough.
I'm usually okay with all of these suggestions. Still, lately, I'm fell in a position where usually the person who reviews my code is our architect (an amazingly talented engineer). He always flags all the minutiae (very politely, of course), and I find it very hard not to comply as I want to ship better stuff.
Funnily enough, a few days ago, I found myself reviewing a colleague's PR and repeating the same behavior. As soon as I saw myself doing it, I deleted these comments, made the suggestions that I judged valuable, and approved.
Thanks for the input! Just replying gave me a lot of clarity on the subject.