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 Episode "In The Forest Of The Night".
THE DOCTOR "The human superpower: forgetting.
If you remembered how things felt, you'd have stopped having wars.
And stopped having babies."