Ferengi Rules of Acquisitions...Let's Quote Them.
I'll start this thread with my favorite rule [#76] Quarrk mentioned in the season 2 episode THE HOMECOMING.
#76. Every once in a while declare peace. It confuses the hell out of your enemies.
Doctor Who--Day Of The Doctor.
Clara: You told me the name you chose was a promise. What was the promise?
Doctor 10: Never cruel or cowardly.
War Doctor: Never give up. Never give in.