The rule is: Use "BUT" as a logical operator, not to seek protection from consequences of your opinion. - Nassim Nicholas Taleb

Wittgenstein's ruler: "Unless you have confidence in the ruler's reliability, if you use a ruler to measure a table you may also be using the table to measure the ruler." (page 224)

Beware of the person who gives advice, telling you that a certain action on your part is “good for you” while it is also good for him, while the harm to you doesn’t directly affect him.

Silver Rule (negative golden rule): Do not do to others what you would not like them to do to you. Note the difference from the Golden Rule, as the silver one prevents busybodies from attempting to run your life.