Thou shalt not submit thy god to market forces.

The Gods Of The Disc have never bothered much about judging the souls of the dead, and so people only go to hell if thats where they believe, in their deepest hearts, that they deserve to go. Which they can't do if they don't know about it. This explains why it is important to shoot missionaries on sight

It was all very well going on about pure logic and how the universe was ruled by logic and the harmony of numbers, but the plain fact of the matter was that the Disc was manifestly traversing space on the back of a giant turtle and the gods had a habit of going round to atheists' houses and smashing their windows.

On the Disc, the Gods aren't so much worshipped, as they are blamed.

The gods," he said. "Imprisoned in a thought. And perhaps they were never more than a dream.

I don't hold with paddlin' with the occult," said Granny firmly. "Once you start paddlin' with the occult you start believing in spirits, and when you start believing in spirits you start believing in demons, and then before you know where you are you're believing in gods. And then you're in trouble."
"But all them things exist," said Nanny Ogg.
"That's no call to go around believing in them. It only encourages 'em.