A Kezayit of Bracha

The third bracha of the birkat kohanim is, "May Hashem raise His face to you and give you peace."  (Bamidbar 6:24 - 6:26)  The Gemara (Brachot 20b) says that the angels objected to this bracha.  They pointed out that elsewhere in the Torah, it says that Hashem "does not raise his face (that is, show favoritism) or accept bribes."  (Dvarim 10:17)  Hashem replied, "In the Torah, I commanded the Jewish People to say the birkat hamazon when they eat and are satisfied.  However, they say birkat hamazon after any meal in which they eat a kezayit of bread, even if they are not satisfied.  How can I not show them favoritism?"

This aggada draws a connection between the birkat kohanim and birkat hamazon.  What is the meaning of this connection?

What does it mean that we say a bracha after eating an olive size of bread, even if we are not satisfied?  It means that even if we are not satisfied with everything in our lives, or in the world, we still thank Hashem for every kezayit of bracha that He gives us.  In response, Hashem focuses on every kezayit of mitzvot that we do, even though He may be unsatisfied with many aspects of our behavior.