Biggest L's....
Individual L's - Stringer as he tried to navigate two worlds and was destroyed in the process. Too smart for the street, but not acute enough for high-end corporate crime and treachery. Honorable mention to Ziggy, Duquan, and the girls within the cargo container.
Collective L's - The Middle Class and impoverished Lower Class as they are caught in a vicious cycle of political strife and corruption with the likes of Carcetti, Royce, Nereese, Davis, Rawles, and Burrell at the top. Sure, your main characters may have met an unhappy ending, but entire generations will be deeply affected by the fukkery of the politicians.