Some people find Donna obnoxious, and I understand that. But I think she’s brilliant. No Tennant companion was as comical and downright fun as Donna was, and even if her first episode was downright dreadful (I’ll never look at spiders the same way again. And that’s not in a fearful way), her tenure with Tennant was phenomenal, and should have been twice as long as it was. It broke my heart that she can essentially never return to the show, and I hope they find a way to retcon that in the future.