One of the worse case scenarios of not being thankful is lack of Faith.
Esau, who was the elder of Isaac's two sons, profaned God's Birthright that was to go him, for a pot of red beans. The Birthright was to go the elder Esau, yet he treated it as wares, like something to traded or sold. So when his brother Jacob had plenty of food when Esau was a hunter and was hungry for lack of game, Jacob asked Esau what he would given him in trade, asking to give away his birthright.
Thus Esau, who's name also is Edom which means 'red', represents atheism, lack of Faith, because it was GOD's BIRTHRIGHT that he gave away like wares.
Also, there is a Hebrew scribe error in Genesis 27 where Esau sees his father after Jacob had stolen his birthright blessing, and Esau begs for a blessing from his father Isaac...
Gen 27:38-39
38 And Esau said unto his father, Hast thou but one blessing, my father? bless me, even me also, O my father. And Esau lifted up his voice, and wept.
39 And Isaac his father answered and said unto him, Behold, thy dwelling shall be the fatness of the earth, and of the dew of heaven from above;
KJV
That blessing to Esau in red above should instead read in the Hebrew, "Behold, thy dwelling shall be AWAY FROM the fatness of the earth, and of the dew of heaven above;". (See E.W. Bullinger's side margin note on this in The Companion Bible.)
That makes sense too, because how could Isaac transfer God's Birthright TWICE? give it to Jacob, and then take it away and give it to Esau? Earlier, when both children were in their mother's womb, because of the stir in her womb, she prayed to God about it. She was told that the younger (Jacob) would rule over the elder (Esau), even though Esau was firstborn.
Esau today represents the Reds, atheistic Communist Russia. (The system, not necessarily all the people, for there are many Christians there).
