Elphaba was never the favorite child, which is saying a lot. Nessarose was crippled and constantly needed Nanny for support. Shell would get into trouble and disappear for certain periods of time. Elphaba is the most mentally stable of the children when they were young, and appears to be the most normal - mentally - as well. Both sisters are described as stubborn and they have a very love/hate relationship.
At school, Elphaba was constantly a victim of prejudice. She would always rather be immersed in a book than in a social clique. Constantly ignored and made fun of because of her skin and hair color, she eventually falls into a friendship with Galinda. At first, it looks like Elphaba will fall prey to a backstabbing best friend, but they grow very close. This is a good thing in Elphaba’s life. She and Galinda grow close, like so many college roommates do over the years.
One thing that many will consider a mistake is Elphaba’s disappearance from Shiz. She left her friends Galinda, Boq, Tibbet, and Crop, as well as her sister and Nanny. Elphaba did this because she could not bear to stay around and be used like a pawn. Elphaba’s visit to the Wizard really made her suspicious. This propelled Elphaba to join a rebel group against the Wizard, that and her hate for Madame Morrible. Without her escape from Shiz, Elphaba would have never met Fiyero. Her story could have been drastically different, but she wouldn’t have been true to herself if she stayed true to herself.
The final scene, where Dorothy gives Elphaba a baptismal splash frees Elphaba. She is saved from her greatest enemy - herself. At the end of the novel, Elphaba has fallen into insanity, and the belief that the Scarecrow is actually Fiyero shows this. She is downgraded, broken, and depressed. Dorothy coming to kill Elphaba - and succeeding - is almost like an indignity to Elphaba, and is probably the most tragic moment of her life. It is the only way Elphaba could be freed of herself, and sadly, she had to die.