4. The Doctor Tells You Not To Do Something, Then Shows You How To Do It
It's been commented on before now, but it remains true - The Doctor's behavior in Tomb of the Cybermen is odd to the point of being completely incomprehensible. at every single juncture in that story he basically says, 'Oh, you should definitely not do 'X'. Which you could easily accomplish by following these three easy steps. But you totally shouldn't do it. Honest.' I'm not sure if the most egregious example is when he tells them that they totally shouldn't go in the electrified doors that he's only just checked to make sure they're safe to touch, or when he points out the door that none of them had noticed thereby getting a least one chipper young technician killed, or perhaps when he goes out of his way to correct the logic diagram to open the great big manhole of icy doom that he's super-sure no one should open. Honestly, if he'd just shut the Hell up at any point in this story everybody would have been just fine. Well, except that first guy that got electrocuted, but nobody cares much about him. I've read a few theories trying to explain exactly why the Doctor behaves like he does in this story, but I think the best is one that Stephen Moffat wrote many years ago now - long before a new Doctor Who was remotely considered possible. Mr. Moffat put forth the theory that the Doctor is just being a total bastard. Occam's Razor suggests that this is the case.