I know they said this one was supposed to be scary, but I didn't expect it to be the Doctor, rather than the monsters, that gave me nightmares.
And this, this, is totally why he shouldn't travel without a companion. Donna talked him down from God-complex-induced craziness once, but there was no Donna beside him this time. Adelaide, although totally awesome, was simply too horrified at the end there to even think about reaching out to him. She just wanted to undo the damage he'd done in the only way she could think of (and that was some gutsy storytelling there. Seriously dark).
The way he talked, so casually, about 'little people'... well, damn. I love Ten and I love Tennant, but both made me feel physically ill, at that point. Oh, Doctor. Don't start down that road. We've seen what lies at the end of it. (It looks remarkably like John Simm. On which related subject: OMGSQUEE)
Ten has long been heading this way, I think, so it was no surprise -- but it was hard to watch. Necessary, though, to lead into the endgame.
I am going to be such a mess, come the finale.