It is said in the film that Ice Cube's character works in an airport in Detroit. When the scene shows Ice Cube at work as a baggage handler, there are mountains in the background. There are no mountains in the Detroit area.
When the scene where the cow is blown up was threatened to be cut due to money constrictions George Clooney paid for the effect out of his own pocket feeling it important to the scene. He was right, the scene was wildly popular with audiences. (Source George Clooney Biography at http://www.tiscali.co.uk/entertainment/film/biographies/george_clooney_biog/5).