3. Donna's Loss
The final episode of Series 4 Journey's End pulls out all the big stars to fight Davros, the creator of the Daleks. We again bump into Mickey, Martha Jones, Rose and the parallel universe Doctor. There's also the Tenth Doctor's severed hand, which interacts with Donna Noble in a manner fit for a Stan Lee serial from the '50s. Donna, through electrocution by Davros, has her own genetic makeup combined with the Doctor's to form DoctorDonna (which incidentally some people absurdly refer to as "the REAL Eleventh Doctor"). But having a Time Lord inside your head isn't all it's cracked up to be. Donna's mind short-circuits, like someone who was just forced to sit through a couple Zack Snyder movies with toothpicks holding their eyelids open. But unlike people who were tricked into seeing that garbage film 300 in the theater, Donna's mind is fortuitously wiped clean; of course, her real tragedy is not that she also saw Sucker Punch, but that all of her memories of travels with the Doctor are gone forever.