When I code review, I differentiate between "code quality" and "opinion". First off, there needs to be a coding standard guideline so that 80% of all issues of "opinion" vs "coding standard" are well defined. This is one of the reasons why I like go, because things like go fmt are the great equalizer.

I probably won't like the variable names people chose but I won't comment on that because that's "my opinion". I will comment on even the smallest bug I see, because that's what we're paid to do. So line by line "perfection" is what I believe we need to strive for in terms of code quality. Maybe not so much "perfection" but "best practices" might be a better way of stating it. We always need to strive for best practices so that our code is predictably easy to maintain, read, etc.