Just watch the first 2 seasons. Some might argue only season 1 is necessary, but I think season 2 gives context to the backstory of the show. These two seasons cover all the important issues and provide an incredibly gripping and emotional story. Seasons 3 and 4 were. . . just absolutely terrible and unwatchable. I made it all the way through season 3, but I only made it through 7 episodes of season 4 before I decided to stop and just read about the ending. The overall story that was written in these last two seasons is just trash. The characters become extremely unlikable, and the story is so boring and irrelevant.