Spoilers are ahead if you have not seen all the seasons of Shameless that are on Netflix. As the show has progressed, however, Debbie has become the clear worst Gallagher out of the whole family.
She used to be such a good caretaker
She used to run the daycare out of her house and was becoming a real adult and person who would save the family like Fiona and then it just went straight downhill.
She helped break her mom out of the psych ward
She helps Frank break Monica out when she really needed to stay in the psych ward. Then Monica just hops in a car and abandons them!
She tries to drown the girl who was bullying her
There is a bully at the pool so Debbie spends all season learning how to hold her breath and then decides that she is just going to hold this girl underwater until she passes out.
She tries to seduce a 20-year-old guy
She tries to act like her friends and tries to be all grown up at like 13 years old. I blame Matt for even interacting with her because holy crap that is illegal but it was an issue on both of their parts.
She basically tortures one of her friend’s girlfriend
She gets jealous because Matt gets a girlfriend his age. She decides to torture this girl by putting a snake in her car and just threatening her in general. The girl then threatens Debbie with a baseball bat. Let's be honest, Debbie deserved it.
She then rapes said, 20-year-old boy!
She gets Matt drunk and then decides to just hop on top of him while he is passed out drunk.
She lies about getting an abortion
She and Fiona go to the clinic because they are both pregnant. She lies to Fiona and tells her that she isn't pregnant. But guess what? She still is and carries her daughter to full term.
She is taking advantage of Neil
Debbie wants to have a good life and a good life for Frannie but she does not really love Neil and is just using him for the money that he got from his accident.
She puts her daughter in harm's way, a lot
She gets in a fight with a homeless woman when she has her daughter strapped to her. Plus she falls asleep holding Frannie and she ends up falling out of her arms.