Related:

• When the personality of a human is involved, exact predictions are hazardous.
  -- McCoy, "The Lights of Zetar," stardate 5725.6...
• What is it in you humans that requires an overwhelming display of emotion in a situation such as this?
  Two men pursue the only reasonable course of action indicated, and yet you feel that something else is necessary....
• Timothy: "Androids are better than humans?" Data: "'Better' is a highly subjective term.
  I do not for example possess the ability to experience emotion as humans do....
• Where there's no emotion, there's no motive for violence.
  -- Spock, "Dagger of the Mind", stardate 2715.1...
• Worry is a human emotion. -- Spock, "Journey to Babel," stardate 3842.4
• Humans do have an amazing capacity for believing what they choose -- and excluding that which is painful.
  -- Spock, "And The Children Shall Lead," stardate 5029.5....
• Humans smile with so little provocation. -- Spock, "Journey to Babel," stardate 3842.3.
• Spock: "Humans have no conception." -- "Amok time", Stardate 3372.7.
• You [humans] are, after all, essentially irrational. -- Spock, "Metamorphosis," stardate 3220.3