OOP: What's up with Harry and Snape?

[greatlit2003]

No: HPFGUIDX 63028

Exactly why does Harry feel a surge of hatred towards Snape as he 
accosts him about to curse Malfoy at the end of OOP? Does anyone else 
think that the relationship (or lack of) between Harry and Snape 
could have been developed further in OOP?

I know that Harry is angry with Snape for taunting Sirius, but he 
also is aware that Sirius returned the favor to Snape on many 
occasions, often going out of his way to be rude (such as the scene 
in his kitchen)

Harry might blame Snape for stopping the Occlumency lessons, but he 
should also know that was his own fault.

Dumbledore already explained that Snape saved Harry's life by 
contacting the Order, telling them about Harry's dream, and then 
going to the forest himself to search for the kids. If Snape hadn't 
done that, Sirius would have survived, but Harry, Ron, Hermione, 
Neville, Luna and Ginny would all be dead.

So why blame Snape? What did he do wrong in this book? Was Harry 
trying to shift the burden of Sirius's death on Snape as an easy 
alternative over the right one, which would have been to apologize 
for his behavior (not shutting out the dreams in spite of repeated 
instructions on Snape's part) and acknowledge that his own weaknesses 
contributed to Sirius's death?

I'm a fan of Snape, so my reading has been a bit biased in his favor. 
I'd appreciate it if anyone can point out the reason for Harry's 
bitterness because I might have overlooked it. Thanks.

greatlit2003
mourning Padfoot :(