Most depressing: It's a tie between Tim dying, and thinking she Lost her powers....and when Max came to find her after 8 years and broke her cuore while explaining how their friendship as children was a lie.
Most Joyful: This one's really tough....Every time everyone is together and everyone's happy makes her happy. Other than that I guess seeing her little brother for the first time. Even though it hurt a bit knowing she could never have a relationship with him, she was really happy that she had a sibling and it gave her hope that the future of her kingdom would be bright..........Also when Ana took her in from the streets, for the obvious reason that Emily got to meet all of these amazing Friends and finally felt at peace with herself in the environment.