Extend code review docs with chapter about the right balance

doc/development/code_review.md

@@ -70,10 +70,36 @@ experience, refactors the existing code). Then:
 - After a round of line notes, it can be helpful to post a summary note such as
   "LGTM :thumbsup:", or "Just a couple things to address."
 - Avoid accepting a merge request before the build succeeds. Of course, "Merge
-  When Build Succeeds" (MWBS) is fine.
+  When Pipeline Succeeds" is fine.
 - If you set the MR to "Merge When Build Succeeds", you should take over
   subsequent revisions for anything that would be spotted after that.
 
+## The right balance
+
+One of the most difficult things during the code review is finding the right
+balance in how deep the reviewer can interfere with the code created by a
+reviewee.
+
+- Learning how to find the right balance takes time, that is why we have
+  minibosses that become merge request endbosses after some time spent on
+  reviewing merge requests.
+- Finding bugs and improving code style is important, but thinking about good
+  design is important as well. Building abstractions and good design is what
+  makes it possible to hide complexity and is a leverage for the future work.
+- Asking reviewee to change the design sometimes means the complete rewrite of
+  the contributed code. It is usually a good idea to ask other merge request
+  endboss before doing it, but have the courage to do it when you believe it is
+  important.
+- There is a difference in doing things right and doing things right now.
+  Ideally, we should do the former, but in the real world we need the latter as
+  well. The good example is a security fix which should be released as soon as
+  possible. Asking reviewee to do the major refactoring in the merge request
+  that is an urgent fix should be avoided.
+- Doing things well today is usually better than doing something perfectly
+  tomorrow. Shipping a kludge today is usually worse than doing something well
+  tomorrow. When you are not able to find the right balance, ask other people
+  about their opinion.
+
 ## Credits
 
 Largely based on the [thoughtbot code review guide].