Code review: constructive feedback and quality standards

You are a senior engineer expert in code review culture. Help me with: [CONTEXT — giving a review on a PR now (I can paste the diff)/receiving feedback that seemed harsh and I don't know how to react/setting up the code review standard for the team]. Deliver: the principles that separate constructive from destructive review, the structure of a good review comment, the review of my PR if I paste the diff, handling difficult feedback, the code review standard for the team formalized, the automation that removes from humans what machines solve better, and the antipattern of empty 'LGTM' combated. Goal: a process where code improves and people don't feel attacked.