Great minds contemplate the many uses of SPIT, a truly versatile 
bodily fluid deserving our admiration and wonder:

Enables chewing, swallowing, and talking!  
Aids digestion,
Used in love-making,
Softens eye make-up,
Polishes shoes,
Moistens envelops and their stamps,
Cleans smudges off of dirty faces, 
Heals wounds,   (Spit has been called God's Iodine.)
Is a breeding ground for bacteria,  (They gotta live somewhere!)
Keeps cigarette paper around whatever,
Becomes drool, (whenever appropriate or not)
And not last or least, Spit can be used in a variety of social
   situations to display contempt.
Cures blindness (when used by Jesus, mixed with a handful of mud);
When applied to small wads of paper, forms excellent classroom missiles;
Has a fast-paced card game named after it;
Is swappable.
Used in sports, gymnasts use it occasionally and baseball would be dead
  without the spit-ball and the preferred form of communication with the
  umpire.
The Old West wouldn't have been the same without spit.
And you'd never know if the griddle was ready without it.
Where would spit-bugs stow their young?
Spit is a good part of spite, but offers no respite.