"DiddyK" comes from Diddy Kong, my all-time favorite fictional character, and "F1" comes from Formula 1, since I'm such an obsessive motorsport fanatic.
Funnily enough, I was originally DiddyKF1Enthusiast on YouTube and a few other places for a while, but I later decided to shorten it to just "DiddyKF1" because I wanted a shorter name and it just ticked and stuck ever since!