Aliens Don't Get Stuck In Air Ducts.

People Don't Alter History Any More Than Birds Alter The Sky, They Just Make Brief Patterns In It.

Cats Will Amusingly Tolerate Humans Only Until Someone Comes Up With A Tin Opener That Can Be Operated With A Paw.

Haven't You Got Any Romance In Your Soul?" Said Magrat Plaintively. "no," Said Granny. "i Ain't. And Stars Don't Care What You Wish, And Magic Don't Make Things Better, And No One Doesn't Get Burned Who Sticks Their Hand In A Fire. If You Want To Amount To Anything As A Witch, Magrat Garlick, You Got To Learn Three Things. What's Real, What's Not Real, And What's The Difference.

Dwarfs Were Not A Naturally Religious Species, But In A World Where Pit Props Could Crack Without Warning And Pockets Of Fire Damp Could Suddenly Explode They'd Seen The Need For Gods As The Sort Of Supernatural Equivalent Of A Hard Hat. Besides, When You Hit Your Thumb With An Eight-pound Hammer It's Nice To Be Able To Blaspheme. It Takes A Very Special And Strong-minded Kind Of Atheist To Jump Up And Down With Their Hand Clasped Under Their Other Armpit And Shout, "oh, Random-fluctuations-in-the-space-time-continuum!" Or "aaargh, Primitive-and-outmoded-concept On A Crutch!

The Book Is Not Completely Written Until Someone Else Has Read It.