In PoA, when Lupin forgets to take his potion, he doesn't actually change until they go outside and the moon comes out from behind a cloud.
How am I supposed to work with this? Why would anybody need that stupid potion if all they had to do during the full moon is stay indoors with the shades drawn?
I'm just going to ignore that particular passage.
I find it interesting, though, that after Lupin changes, he's then referred to as "the werewolf" and "it" rather than "Lupin" and "him".
Also, snow day! The buses are running, the schools are open, but my office is closed! I think this is a gift from the fic gods so I can get a good start on my Snape/Lupin fic, which I've been putting off. I hope that makes all the kids who have to trudge to school through the snow feel better.