First, Desa, reading Roman literature about the Emperors is like reading the New York Times about Republican Presidents or the Dispatch about Republican legislators.   Roman literature was written for the wealthy senatorial and knightly classes and reflected their beliefs and interests; ironically, most of the emperors were populists and relied on the Roman mob for their power.   Consequently, there was never much love lost between the emperors and the Roman elite.   If you wanted insult a Roman politician, you accused him of homosexuality and of incest with his sister(s) or mother.   There is just as much evidence that Caligula was an able administrator who took on some powerful vested interests as there is that he was some sort of perverted monster, but just as today, the elite got to write the history.