Birkat HaMazon (Grace After Meals) and Satisfaction

(10) When you have eaten, and you are satisfied, give thanks to Hashem your Gd for the good land which Hashem has given you.

One is forbidden to derive benefit from this world, which is the property of Gd, without reciting a blessing beforehand. And anyone who derives benefit from this world without a blessing, it is as if he is guilty of misuse of a consecrated object.

[O]ne who eats a quantity of food that does not satisfy his hunger is [still] obligated by rabbinic law to recite Grace after Meals, the Gemara cites a related homiletic interpretation. Rav Avira taught, sometimes he said it in the name of Rabbi Ami, and sometimes he said it in the name of Rabbi Asi: The ministering angels said before the Holy One, Blessed be He: Master of the Universe, in Your Torah it is written: “The great, mighty and awesome God who favors no one and takes no bribe” (Deuteronomy 10:17), yet You, nevertheless, show favor to Israel, as it is written: “The Lord shall show favor to you and give you peace” (Numbers 6:26). He replied to them: And how can I not show favor to Israel, as I wrote for them in the Torah: “And you shall eat and be satisfied, and bless the Lord your God” (Deuteronomy 8:10), meaning that there is no obligation to bless the Lord until one is satiated; yet they are exacting with themselves to recite Grace after Meals even if they have eaten a piece of bread the size of an olive. Since they go beyond the requirements of the law, they are worthy of favor.