Her Personality:

Susie is known for being rude, vulgar, as well as making sarcastic or brutally honest remarks. She can threaten with physical violence, such as biting off someone's face. In a Dark World, she is willing to attack Darkners if they are perceived as enemies.

However, Susie has a different temperament to those who are kind to her. With friends, she is expressive, willing to talk about herself, and ask for their opinions. Susie favors teasing her friends, and is more observant of their emotions. She makes an effort to be considerate, and tries to not push them to talk about a stressful issue. Susie is also loyal, readily wanting to assist a friend if they are in danger or troubled.

She likes compliments, and is easily flattered. Susie also enjoys causing mischief and childish antics, such as trying to fit in a freezer. She appears to like eating in general, including non-food items, and receiving gifts. She is possessive of items given to her.[1]

Susie is also implied to have self-esteem issues. She appears convinced that no one likes her, and is oblivious to Noelle's crush on her. She is also aware that she struggles academically.[2]

Ref: https://www.youtube.com/watch?v=0oSOz8-neO8&t=3s