4. Donna Loses Her Memory Journey's End
This is where I think this list kicks it up a notch; its not so much puppy kicking as puppy mauling. So, it may be obvious to an avid Who watcher which ones are coming next, but here they are anyway. After ridding the universe from the Daleks, the Doctor takes all of his friends home and says goodbye to them all. Until its just Donna left in the TARDIS, or rather, the Doctor-Donna; part human, part Timelord. Shes now brilliantly clever but her mind is too full it burns from all the Timelord knowledge. The Doctor has to wipe her memory to save her life. Were sent into flashback, looking at all of the amazing things that Donna had seen whilst travelling with the Doctor, which she doesnt get to remember. When its done, she slumps down into his arms and he takes her home. He speaks to her family and they mourn the person that she had become. Then Donna enters and the Doctor hides his true identity. She responds absently and when he goes to leave, she couldnt care less. Love Donna or hate her; its sad to see her go. She had so much potential and was so happy with the Doctor, its such a cruel fate and it definitely brings a tear to the eye.