"It is difficult to get a man to understand something, when his salary depends on his not understanding it." -- Upton Sinclair

Old quote. Explains a lot.

Runner up in the "Some things haven't changed", same guy:

"The great corporation which employed you lied to you, and lied to the whole country - from top to bottom it was nothing but one gigantic lie"

(Yes: he was a Socialist then a Democrat, but truth is where you find it)