No one means all he says, and yet very few say all they mean, for words are slipperyand thought is viscous.

-Adams, Henry Brooks
  The Education of Henry  Adams, ch.31,'The Grammar of Science'.

   The rising unto place is laborious, and by pains men come to greater pains; and it is sometimes base, and by indignities men come to dignities. The standing is slippery, and theregressiseithera downfall, orat least an eclipse, which is a melancholy thing: Cum non sis qui fueris, non esse cur velis vivere.

-Bacon, Francis,Viscount St Albans
  Essays, no.11,'Of Great Place'. The Latin is taken from Cicero's Familiar Letters, and translates as:'When you are not what you were, there is no reason to live.'

The real world is not easy to live in. It is rough; it is slippery. Without the most clear-eyed adjustments we fall and get crushed. A man must stay sober: not always, but most of the time.

-Day, Clarence Shepard
The Crow's Nest,'In His Baby Blue Ship'.

You're blessed with a woman's brain: vague, slippery, inexact, interested only inthe personal aspect of a thing.

-Lindesay Robertson ne¤  e Richardson
  The Getting ofWisdom, ch.9.