Pinchas – Just Say Thank You

Why does Hashem refer to the Korbanos (sacrifices) as 'My sacrifice, My bread, My fire-offering?' Does Hashem need to 'eat' the sacrificial animals or drink the wine and water libations? What does the passuk in Tehillim 50 mean when it says that Hashem does not care about the sacrifices, all He wants is a 'Gratitude offering?' 

What is the concept of the 'wicked one' who speaks of lofty spiritual matters, but is actually spiritually bankrupt? Why would Hashem, Who has everything, ask something of the human being, who honestly has so little? What is it really that we offer Hashem, as it were, which brings Him satisfaction?