In short: I once read an explanation of Ramchal that HaShem didn't create the world for His own benefit, because He doesn't need anything, so all that He had created has been created for 'another'. A lot of commentaries speak about HaShem being Koelo Tov, (He is complete, absolute, perfect etc. Good). And Ramak teaches that one who is inherently good, does good. So the conclusion of all this was that HaShem created to world to bestow His Goodness.
Anyway, now I came across of an explanation regarding the term 'Bracha': which stated that this term is related with the term Breicha, meaning a flowing stream, or source of water; and by such it is interpreted as a stream of Divine goodness flowing downward into the world.
HaShem is the source of all blessings. When we say Birkat HaMazon, the grace after the meal, we acknowledge that all our blessings emanate from Him, and we thank Him for all the goodness we receive on a constant basis. When we express a bracha, it facilitates a Divine flow of blessings upon us from Above. We acknowledge that all our blessings in life come from the Ultimate source of all blessings.
All our brachot (often recited starting with the words Baruch Atah) seem to affirm this view. But looking at the Tenach we see HaShem bless man, man bless HaShem, and man bless man. How do I need to understand this stream of divine goodness? How is it able to flow from man to G'd and man to man?