Skilled as he was ‘in discerning a man’s secret wishes’, he brought a lethal and merciless precision to the art of mocking them. […] In truth, those who imagined that the only purpose of inflicting punishment was to educate the Roman people in the responsibilities of citizenship were grievously behind the times. Caligula made sport with senators so as to intimidate the entire elite – but also because it amused him. If sometimes the vengeance he meted out to his victims was necessarily as swift as it was discreet, then his preference in general was for toying with them in public. ‘Only strike such blows as permit a man to know he’s dying.’ The maxim was one that Caligula treasured.
– Tom Holland, Dynasty: The Rise and Fall of the House of Caesar (2015)