Lindsay Lohan and Paris Hilton have been having trouble on their respective movie sets. A source on the set of I Know Who Killed Me says that ever since she went to the Wonderland clinic, Lindsay Lohan has been trailed by a "sober coach" as well as an entourage, and has been "moody and is making everyone miserable around her. She'll be late and sometimes won't come out of her trailer." As for Paris Hilton, a source says she's been arriving late on the set of The Hottie and the Nottie and has trouble learning her lines. A source adds: "Everyone is really fed up with her right now." I'm not sure how this is news. I mean, sure, memorizing lines is easy for the average person, but expecting Paris Hilton to do it with the brain she was given is like expecting a mouse to build you a working rocket ship.