American Idol's most famous quitter, Mario Vazquez, poked a little fun at his current situation on Tuesday's Late Show with David Letterman. Presenting the "Top 10 Reasons I Quit American Idol," Vazquez only made it to the No. 4 reason, announcing, "Screw it — I'm quitting this, too." (I hope he told his mother first this time.) Meanwhile, Vazquez's exit doesn't seem to be hurting Idol's ratings. Last night's performance edition attracted more than 28 million viewers.