Stupidity

“It’s easy to identify people who can’t count to ten. They’re in front of you in the supermarket express line.”
June Henderson

“A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.”
Douglas Adams

“The stupid are deaf to the truth; they hear, but think that the wisdom applies to someone else.”
Heraclitus

“Genius may have its limitations, but stupidity is not thus handicapped." 
Elbert Green Hubbard 

“If stupidity got us into this mess, then why can’t it get us out?”
Will Rogers