Unlike Young Justice which was canceled unexpectingly when they thought they would get a third season and it ended on a cliffhanger, with Teen Titans they pretty much knew from the start that Season 5 would be the end. While they concluded the Brotherhood of Evil storyline, the last episode has Terra come back to life with no memory of her past self. That would be fine, but there was also a weird alien/robot thing they fought in the episode with no backstory and no conclusion. The episode ends with the fight against the robot/alien still going on while Beast Boy goes to join them. So in general: - Terra returns to life with no explanation and loses her memory - Titans fight a new weird alien/robot with no conclusion And lastly they never explained who Red X was, which was a mystery building in Season 2. Why end the show on a cliffhanger when everyone on the staff knew the show was over?