13. Michael Hyatt as Brianna Barksdale on The Wire
The sister of West Baltimore drug kingpin Avon Barksdale (Wood Harris), Brianna was a well paid advisor. Her advice to him may have been sound, but it certainly wasn't for her own son, D'Angelo (Larry Gilliard Jr.). For instance, she introduced him to the family business despite having enough money to, you know, maybe steer him clear of the corners.
At the end of Season One, when D was arrested while trafficking drugs for his uncle and he learned that the crew murdered Wallace (Michael B. Jordan), one of his teenage underlings, he decided to flip on everyone. However, he pulled out of his plea deal because his mom convinced him that he had a duty to his "family." It should be noted that, while trying to do his time quietly and isolate himself from the crew, his uncle's cautious partner, Stringer Bell (Idris Elba), had him strangled to death, his murder staged to look like a suicide by hanging, to eliminate the possibility of testifying against the organization. Thanks for the advice, ma!