Originating from "shit bastard", however the meaning is slightly changed... a shit bastard is a person who is annoying for some reason, the phrase "shitbas" is used for describing something or an explanation of annoyance or displeasure.
Tom: "Man, i lost the car keys, way out there in the jungle"
Tim: "Argh Tom, you shit bastard, how could you do that?!"
***
"Crap, my CD is broken!"
"Na, don't matter, it was shitbas anyway..."
***
"Shitbas! Just hit my faffing head on the door!"
Tim: "Argh Tom, you shit bastard, how could you do that?!"
***
"Crap, my CD is broken!"
"Na, don't matter, it was shitbas anyway..."
***
"Shitbas! Just hit my faffing head on the door!"
by the fatboy racer July 10, 2005