The Primal Sin: Unthankfulness
Al Mohler ruminates on Romans 1:20-22 and the giving of thanks to God. It's worth reading, check it out. He describes the sin of un-thankfulness:
"This remarkable passage has at its center an indictment of thanklessness. They did not honor Him as God or give thanks. Paul wants us to understand that the refusal to honor God and give thanks is a raw form of the primal sin. Theologians have long debated the foundational sin -- and answers have ranged from lust to pride. Nevertheless, it would seem that being unthankful, refusing to recognize God as the source of all good things, is very close to the essence of the primal sin."
Also, he early makes the point that in a purely naturalistic worldview thanksgiving, both as an act and as a holiday, is essentially pointless. We never think of giving thanks to rocks, trees, stars, or inanimate objects or to ideologies, beliefs, or philosophical systems because giving thanks is a personal exchange between two persons. Without someone to thank then how can one give thanks?