Revealing mistake: When Rosemary is carrying Hal out of the front door if you look closely at his shirt you can see it moving around from the wires that are keeping him suspended. (01:40:00)
Revealing mistake: At the end of the film when Hal and Rosemary reunite, Rosemary hugs Hal. In one shot, you can see Paltrow's thin hands, and beneath her shirt sleeve, the end of her fat suit's arm.
Revealing mistake: As they're leaving together from Rosie's house at the end, Rosie stands up in the car to wave at people. The car sinks down with her weight when she puts her second foot inside the car, not when she takes it off the ground which is when all her weight would be on the car. (01:40:20)
Revealing mistake: When the "real" Ralph is first shown at the Peace Corp office, he has an unattractive and nerdy appearance/voice. When arriving at Rosemary's party in the car, when saying "Amen to that", he suddenly looks fairly attractive and his voice sounds less nerdy. Then when saying "Good luck Hal", his voice becomes nerdy again.
Chosen answer: Yes. Just as Hal sees many unattractive and/or overweight women to be thin and beautiful due to their true personalities, he sees Nurse "Sourpuss" - who is a beautiful woman - to be old and ugly due to hers.
Jeff Swanson