Why Occlumency lessons failed?

[kmcbears1]

No: HPFGUIDX 116408


There are many minor reasons why the Occlumency lessons failed, 
Snape's or Harry's attitude, bad teaching methods (Snape), not 
practicing (Harry).

IMO the main reason the lessons failed was that Harry's curiousity 
was tweaked before the lessons began.  Harry had been dreaming about 
the corridor for months before Arthur's attack indicating the need 
for lessons.

I think they would have failed even if DD was teaching.  Harry has an 
enormous need to delve into the unknown when his curiousity was 
peaked.  Even Voldemort knows this fact about Harry, and initially 
used his mind-sharing to give Harry a compulsion to get the prophesy 
from the MOM.  

Harry did not want to stop the dreams.

-kmc