David Spade uses his usual trademark disdain for his subject matter -- in this case his own character, a kind of half-southern white trash, half-California rocker dude named Joe Dirt. He works as a janitor in a radio station and has big dreams and bigger hair. Through a bizarre sequence of events, he goes on the air one day to be interviewed by L.A.'s most notorious smartass/foulmouth, played with zest by Dennis Miller, and tells his life's story on the air.
We never get to know or care about Joe Dirt, since Spade only wants to ridicule him, never understand him. We're treated to the now-obligatory gross-out scene, in this instance a dog's testicles frozen to a porch... or perhaps it's the scene where Joe has sex with a girl he believes is his sister... there are too many to nail down just one. Comedy isn't about dialogue or situations anymore, it's about how far can you push it. Can you show the sperm in the hair? Can you show the kid having sex with an apple pie? How much can you get away with because the audience, long having forgotten that comedy isn't supposed to just shock you, doesn't know the difference?
The movie wasn't at all funny. It was mean-spirited to the point of cruelty, completely without structure, totally predictable and instantly forgettable. It was exactly, precisely, the model of what is wrong with comedy today.