Rule Zero 

When you're trying to figure out whether doing something is a good idea or not, there are various rules that come in to play, such as Have Fun, Do No Harm, Have Fun (again), What Happens in Vegas, etc.

Rule Zero, the rule that always comes before all the others, the most important, basic rule of doing anything is: "Don't be on fire."

- I can't get this bbq to light.
- Here, use some petrol.
- I am not breaking Rule Zero to cook a burger.

--
- Hey, let's see what happens if I fill my foreskin with lighter fluid and light it.
- I am invoking Rule... wait... yeah, go ahead, that'll be funny.

Rule Zero by tbrd June 16, 2010

Rule zero 

A rule on the internet which stands for don’t fuck with cats

Luka Magnotta broke rule zero when he killed 2 kittens.

Rule zero by VSCOboy3000 December 20, 2019

Rule Zero 

The customer always lies.

The customer said this happened. Dude...Remember Rule Zero!

Rule Zero by Tech Support Rep February 1, 2012

Rule Zero of the Internet 

Rule zero of the internet refers to the most important rule of the internet. Don't f**k with cats.

Hey do you know rule zero of the internet? It's don't f**k with cats.

Rule Zero of the Internet by Phenoniem January 13, 2022

Internet rule zero 

Rule 0 of the internet:Don't fuck with cats.

Garry: Hey! look at this stupid cat lol!
You (most likely):Internet rule zero, RULE ZER-OH

Internet rule zero by Internet Rules 101 July 29, 2022