Automatic Sayings Generator

Never tell all that you know; for he who tells all that he knows, often tells more than he knows.

Never spend all that you earn; for he who spends all that he earns, often spends more than he earns.

Never guarantee all that you undertake; for he who guarantees all that he undertakes, often guarantees more than he undertakes.

Never discuss all that you hear; for he who discusses all that he hears, often discusses more than he hears.

Never eat all that you can; for he who eats all that he can, often eats more than he can.

Ran across this one once upon a time in an old puzzle booklet from the 1930s. A long, long list of sayings like these, and more, all constructed on the same pattern: Never x all that you y... Odd, they all more or less made sense: it was a funny sort of "sense," a fortune-cookie sense; but I got the impression that it could have been extended indefinitely.