The moral of the series, if one chooses to accept the final season, is: if there's someone after you, make sure you kill them. Never walk away. Never try to do the right thing. Just fucking kill them.
It was stupid to turn Dexter to Revenge, with all these meaningless twists and "overwhelming" emotions. I'm sure there was a way to let Debra go with more dignity, she's not fucking Declan Porter!