Silly quotes from actual consumer product packages and instructions,
     as well as from newspapers:

On a bag of JONNY CAT cat litter: "JONNY CAT is the best value for your money.
A 20-pound bag of JONNY CAT contains 25% more litter than 16-pound bags, and
43% more than 14-pound bags!"

From a kid's Superman costume for Halloween (stitched into the cape's tag):
"Warning: Use of This Device Does Not Enable Wearer To Fly."

From a Pop-Tart box: "Warning: Pastry Filling May Be Hot When Heated."  

From a newspaper article: "A congressionally funded study has determined that
many smokers are ignoring the warning labels on cigarette packages."
  
From a hair blow-dryer instruction sheet: "Warning: Do Not Use While Sleeping."

On the package for Top Cog fan belts (for automobiles): "Do not change the belt
while the engine is running."

From a Boston Globe piece, during a 1973 summer heat wave describing ways to
beat the heat: "No. 1 - Stay out of the direct rays of the sun."          

Found on the inside of a pull top lid of a liquid radiator sealant: "Caution:
DO NOT LICK LID."          

Written on the back of one of those things you put in your car windshield on
sunny days when you park to keep your dash from melting: "DO NOT OPERATE
VEHICLE WITH SCREEN IN PLACE."          

From the Indigo PC Owners Manual pp.6-9: "Hardware Dos and Don'ts: Do not
dangle the mouse by its cable or throw mouse at co-workers."  
   
On a box of those cloth roller towels in a restroom: "Warning!  Improper use
may cause serious injury or death!"