"stupidity" -- some appreciations

Ran across this Internet site this morning. It seems to be devoted to quotations about stupidity... several if which caught my eye:
"Never attribute to malice that which can be adequately explained by stupidity."
-Anonymous
"The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt."
-Bertrand Russell
"When a stupid man is doing something he is ashamed of- he always declares that it is his duty."
-George Bernard Shaw
"It is dangerous to be sincere unless you are also stupid."
-George Bernard Shaw 
"The only thing that ever consoles man for the stupid things he does is the praise he always gives himself for doing them."
-Oscar Wilde 
"One must be a little foolish- if one does not want to be even more stupid."
-Michel de Montaigne