It may be obvious, but making bad choices can get you stuck in some bad situations. Sometimes when people do something, even if it's not bad, they dont consider what the consequences of thier actions may be. When you makes choices, knowing what the consequences may be can keep you out of some bad situations.
Grete Samsa, Gregor's sister, most definitely goes through a "metamorphosis" as does every member of the family. Before Gregor's change, Grete is described as a "useless" daughter. She has taken violin lessons, but she isn't very good. She doesn't leave the house often. She is timid and seemingly afraid of the world.