When someone just cannot stop being a smart ass or facetious, beyond just sarcastic, to the point of being obnoxious.
That jerk seems to have a serious case of obsessive compulsive facetiolism.
Definition of facetiolism:
When someone just can't stop being a smart-ass or facetious, beyond just sarcastic, to the point they become obnoxious.
"That jerk seems to have a serious case of obsessive, compulsive facetiolism. Maybe someone should suggest that he attend a Smart-ass Anonymous meeting to get help!"