We've had this discussion before....*sigh* But, I don't think we really came to any conclusion as to why. There were a lot of...speculations and theories, but nothing solid.
A few ideas (namely mine...) were as follows
1. Harry was too young to really grasp the full meaning of his parents death, therefor, it didn't really matter.
2. Quirrell's death meant about as much to Harry as the sock he gave to Dobby, so it wouldn't really matter.
3. Quirrell was possessed by the big VD, therefor, since Voldemort didn't die, Quirrell's death didn't really count...(maybe???)
4. Cedric dying really hit Harry hard, it was his first real taste of serious (waaaaahhhh) loss....
Anyway, like I said, someone who read the last dicussion on this topic can...add more. Or correct me if I'm wrong....(I dare you...)
