Why a top movie?

Rating: 3/10 (10 May 2008)

I need someone to explain to me why this movie is regarded as one of the top movies of 2007?
No question about Daniel Day-Lewis' brilliance in acting, but IMO the theme of the movie is just nonexistent.
What is the purpose of the story? you can't say that all rich men at that time period were like Daniel Plainview.
Plainview's brutal nature is totally unclear until a certain part of the movie, when he killed Henry.
Why does some scenes progress so slowly? (i don't consider that as gifted directing!) I also cannot understand the significance of religion...i hope someone can explain
anyways if I am wrong please correct me, thats my own opinion after all.