Nature abhors a lot of things, including vacuums, ships called the Marie Celeste, and the chuck keys for electric drills.
It was said that life was cheap in Ankh-Morpork. This was of course, completely wrong. Life was often very expensive; you could get death for free.
Mere animals couldn’t possibly manage to act like this. You need to be a human being to be really stupid.
Never trust a species that grins all the time. It’s up to something.
All assassins had a full-length mirror in their rooms, because it would be a terrible insult to anyone to kill them when you were badly dressed.