Corrected entry: When Moaning Myrtle is in the bathtub with Harry, she doesn't cause the water to move, which would seem acceptable considering she is a ghost. However, when she dives into the toilet in Harry Potter and the Chamber of Secrets, she causes an almighty splash.
Jazetopher
10th Feb 2007
Correction: Being a ghost, she can "choose" to either pass through an object, or interact with it. This being the case, she does not have to be shown interacting with anything unless she wants to. When she makes the almighty splash, she was upset. This is similar to a child slamming a door when angry, to make a point that they are not happy.
Jazetopher