1. The End of Time Parts 1 And 2
The return of Wilfred and the Master. Another complicated plot with twists and turns and hints and humor. We hear the Doctor speak of regeneration - 'It feels like dying, everything I am dies, some new man goes sauntering away and I'm dead.' After saving the world for the last time, he knows he is doomed and spends his last days making sure his friends are thriving. At the very end, having met Rose for the first and last time, the Ood sing him to his death. I am always sobbing at this scene. David Tennant is my favorite Doctor of all time.
The Questions: What legacy do you leave behind? How will people remember you? Is that a good thing? Go forth and be brilliant. Go adventuring, have fun, love, and be the best version of you, here and now. We never know if we have a tomorrow, so best of luck to you!