Well, reality tends to be depressing doesn't it? ;)
You are right, the stories are not depressing in the strict sense of the word. I'm trying to think of how one should call them--
They have a certain suffocating atmosphere to them, which very much has to do with Remus' frame of mind I guess. He is really trapped in his body and self--
On the other hand, some aspects depress me because I know them so well *errm*
But what I think I meant was the following: You are most *believable* when you are "depressing" (which is connected to being realistic); with the "happy end" in Things-- you were getting less realistic: I just didn't quite understand why it happened-- apart from giving us (and poor Remus) that whatsitcalled gratuitious?? sex ;P (which isn't a bad thing in itself)--
I find you are best when you take reality by the neck and shake it and force us to look in its face--
It's hard to combine that with Happy Endings, but not impossible I guess.
But never mind-- it's good that you are not perfect, or I would faint and fall to the ground instantly ;D

BTW It's interesting that you had a hard time writing Sirius, too. I've had my own wrestling match with that little critter recently...