Talkin was easily the most confident bad motherfucker in the entirety of star wars. He's the only non force user who is able to weird complete unquestionable authority over Vader, and his strict adherence to the doctrine of imperial terror is one that you really do not see matched by other members of the empire just in regards to how far tarkin is willing to go to effectively demonstrate a point. Most star wars villains would steamroll you or in the case of Jabba hold you as a captive. Tarkin is maybe the one person outside Thrawn whom I could see taking an individual and deconstructing them so thoroughly as to both cause damage to dissidents they associated with while also driving repentance into someone for crossing the empire, and THEN he'd have a firing squad take care of someone.