The lineup scene. Singer knew that would be a major part of the film, so the actors did take after take. Eventually, they got bored and started goofing around and acting annoyed just like people who were really pulled into a police lineup would.The line they had to read didn't help, and the actors had a hard time keeping a straight face saying it repeatedly. To make things worse, one of the actors ate something earlier that made him a farting machine (Kevin Pollak claims the guilty party was Benicio del Toro, but del Toro only says that "someone" ruined twelve takes in a row by farting). Everything fell apart from there.
Hockney gives a straight reading, but then McManus sets the tone for the rest of the lineup: