according to caesar, what are three things make cassius dangeroous ?

Caesar turns to Antony and remarks, "Let me have men about me that are fat, / Sleek-headed men, and such as sleep a-nights. / Yon Cassius has a lean and hungry look. / He thinks too much. Such men are dangerous" (1.2.193-196). Antony dismisses Caesar's concern, but Caesar is not convinced that Cassius is completely trustworthy.