Explain some of the reasons Caesar gives for his mistrust of Cassius

Cassius can be seen as a man who has gone to the extreme in cultivating his public persona. Caesar, describing his distrust of Cassius, tells Antony that the problem with Cassius is his lack of a private life—his seeming refusal to acknowledge his own sensibilities or to nurture his own spirit. Such a man, Caesar fears, will let nothing interfere with his ambition. Indeed, Cassius lacks all sense of personal honor and shows himself to be a ruthless schemer.