[lhnz]

In my estimation, most places have the opposite problem: everybody approves the code without looking through it, and the only comments that are left are stylistic problems.

Good code reviews spot real bugs and provide solutions and explanations that help the owner to improve their branch. It's completely constructive and feels like going out of your way to way to help them and paying attention to what is meaningful -- the vibe should be a bit like "doorman at a posh hotel providing excellent service", so not disrespectful at all. Also, if you're nitpicking, it's a sign of lack of focus...