And Harry inadvertantly defends Snape against Hermione, which gets very interesting. Hm, if OotP was the teenage rebellion book, then HBP was the teenage obedience book, with the way Harry claimed he was Dumbledore's man, and actually took Snape's advice via proxy of book.

I'd think Snape would be very good at compartmentalizing, else he wouldn't make a good spy for whichever side he's on. Then again, he can't tell the difference between Harry and James, and isn't good at being professional and objective. Or maybe he only does that when his life is in danger.