Related:

• An egotist thinks he's in the groove when he's in a rut.
• None of our men are "experts." We have most unfortunately found it necessary to get rid of a man as soon as he thinks himself an expert -- because no one ever considers himself expert if he really knows his job.
  A man who knows a job sees so much more to be done than he has done, that he is always pressing forward and never gives up an instant of thought to how good and how efficient he is....
• None of our men are "experts." We have most unfortunately found it necessary to get rid of a man as soon as he thinks himself an expert -- because no one ever considers himself expert if he really knows his job.
  A man who knows a job sees so much more to be done than he has done, that he is always pressing forward and never gives up an instant of thought to how good and how efficient he is....
• He was like a child who thinks he sees the outline of an animal in the pebbles on a beach and immediately rearranges them here and there until there can be no possible question.
  -- B.F. Skinner Walden Two...
• He who laughs last thinks slowest!
• When a man and a women argue, it is often the stupidest of the two who thinks He has won.
• The man who says what he thinks is finished, and the man who thinks what he says is an idiot.
• He who fears death dies every time he thinks of it.