I have to admit - I loved this story as a kid, but as the years go on, I've become more fascinated in the many behind the scenes issues that were hampering the production at the time.
I remember even thinking as a child that Tom Baker's hair looked quite different than usual. Only years later did I read that Baker was so ill at the time that his hair was no longer able to retain its natural curl, and had to be curled by the hair and makeup people before work on State of Decay started. (I still haven't found out what exact illness had afflicted him, though. What kind of illness uncurls hair?)
Of course, the funnest thing to do when watching this story is try to pick out the moments when Tom Baker and Lalla Ward were getting along off camera, and when they were yelling at each from across the room. Witness their first two scenes together in Episode One. Romana tells the Doctor, "You really are wonderful!" (a compliment returned by The Doctor later in Episode Three in a scene that positively feels post-coital). Then cut to the location shot, filmed weeks earlier, of The Doctor and Romana exiting the TARDIS, barely able to look at each other. Sad and lovely at the same time.
Ah, but there, a little less than ten minutes into the episode, I realize that the immediate future of the show isn't as bright as I remembered, because Adric has just walked into the console room. It reminds me of the first few minutes of The Phantom Menace, which is an enjoyable romp where we're first introduced to the Jedi at their peak, slicing and dicing droids everywhere using only the power of the force. Every time I watch that movie, I start to think to myself, "Why did everyone, including me, hate this movie so much?". And then Jar Jar shows up (and then as if that wasn't bad enough, Mannequin Skywalker appears a few minutes later) and it all comes flowing back.
Look at the way Matthew Waterhouse walks into the console room. I can imagine director Peter Moffatt saying to him before the scene, "OK, Matthew, just walk naturally across the room and then stop when K-9 tells you to". And then look how Waterhouse walks. You can almost see him saying to himself "Walking naturally...walking naturally..." as he bounces unnaturally across the floor with a stupid grin on his face. No one walks like that! What a tepid start for the actor in his first story in production. He didn't seem this bad in Full Circle. Did he take acting lessons in between this story and that one?