A lot of people don't know, but she was legally blind. She had a hard time with the diving board scene in Caddyshack.
Another tidbit, during the making of Caddyshack, she saved Rodney Dangerfield from jumping off the movie during initial shooting. Rodney did a scene where he was making wisecracks at Judge Smales (Ted Knight) while he was trying to tee off and it was really funny, but no one laughed and the director, Harold Ramis (one of my favorite people in Hollywood all time BTW) stood there stoic.
Rodney marched off the set into the trailer and Morgan followed him to see what was wrong. When she went into the trailer, Rodney was almost in tears and told her that he was bombing because no one was laughing (this was Rodney's first major movie role as he had only done bit parts in the past). Rodney was a standup comedian and laughs were the metric of success. Morgan sat down with him and explained that in the movies, despite the fact that he was hysterical in the scene, no one can laugh because it would ruin the sound track, something Rodney apparently didn't know. So in essence, Morgan saved the film as it wouldn't have been what it was without Rodney.