The idea that Joe Adonis was vain came from reporters who claimed he made up his nickname. After the Dotos came to America they started going by the last name of Adone, and that easily got converted to Adonis. I don't know why they went by Adone, but they did and it started when Adonis was just a boy, so he had nothing to do with it. Many of the nicknames came from their real names, like Chin came from Vincenzo and Lucky came from Lucania. One of the reasons we don't know more about Adonis is because the FBI agents who debriefed him and questioned him didn't do a good job. Plain and simple.