Woo boring weekend!

OK, this is actually a little bit embarassing. The highlight of my weekend was seeing teh new Harry Potter movie: The Half-Blood Prince. Oh, and it gets worse - I saw it with my mum. Laaaaaaaaaaaaaaaaaaaaaame!
On the plus side, I thought the movie was quite good. The acting has improved out of sight, the adaptation wasn’t terrible and some bits were actually quite funny. Still, I have some questions:
a) Was I the only person who laughed when Ron said “The sorting hat came out and told us all to be brave and strong in these difficult times…But that’s easy for it to say..I mean, it’s a hat innit?” (The joke is even funnier because the sorting hat does get whacked, in HP & TDH.)
b) At the end, how can Harry not see that Snape is playing the Death Eaters? Think about what just happened, you tool!
c) Am I the only person who thinks that Luna Lovegood is the best character in the whole series? I hope she actually gets to do things in the HP & TDH movies.