8. Fourth Doctor - The Ribos Operation (1978)
1978-1979 was an intriguing period for Doctor Who, back then it still starred Tom Baker, often considered to be THE Doctor, and famed writer Douglas Adams had taken the helm for seasons 16 and 17, and he oversaw an experiment. Namely, all of season 16 was to be one encompassing story arc, and in it, the Doctor is assigned by the White Guardian to find the six segments to The Key To Time, which have been scattered about through the space/time continuum. So, the next six serials handle the account of how the Doctor finds the Key, piece by piece. Neat concept, right? Except the story got off to such..... a..... slow.... start. Here I am referring to the debut serial of season 16, The Ribos Operation. The Doctor and his new companion (Time Lady Romana) land on the planet Ribos, which has a similar appearance to a medieval Russian town. They discover the first piece of the Key to Time, but it has been used as part of the local kingdom's crown jewels and is on display, under a heavy guard. So the Doctor and Romana find a way to trick the guards out of the room, grab the jewels, go on a brief chase through tunnels, and leave. I summarized all that in one paragraph. Know how long it takes to watch? Eighty minutes. I can understand the classic series' approach to doing multi-episode serials and how it allowed all the stories to develop naturally, with sub-plots and character development galore. In fact, I prefer that method to the single episode format they use now. But this episode had none of that. It's a flat, lifeless story that got dragged on far beyond its natural runtime.
If You'd Like a Good Tom Baker Story: Wow, too many to list. A few are The Ark in Space, Genesis of the Daleks, Pyramids of Mars, the Deadly Assassin, Talons of Weng-Chiang, or the City of Death. Again, to name a few.