Mostly pride/goofing around (he's a huge Weird Al fan, as well as a big karaoke fan), though he admitted before he started that there was no way he would get even a quarter of the way through the middle part....was that pride or just forgetting the middle bit? I pride myself on keeping up with fast singing and that bit is insane.
"My mother disrespected me once. ONCE!"The song was commissioned for the Michael Keaton Gangster-spoof, Johhny Dangerously. Which ... is actually a rather fun flick? I wound up watching it on a flight's streaming service, of all things. So that's fun.