The opening parshios of Sefer Shmos provide keen insight into the significance of hakoras hatov, thankfulness and appreciation. The Torah emphasizes the failure of Paroh to recognize the goodness of Yosef Hatzaddik, "Vayakam melech chadash al mitzrayim asher lo yadah es yosef."
Later, the very same Paroh would deny Hashem. The medrash links these two acts of denial, teaching us that one who fails to recognize and appreciate the kindness and graciousness of others will ultimately deny the goodness of Hashem.
Similarly, the Chinuch (Mitzvah 33) emphasizes hakoras hatov as the foundation of the mitzvah of kibbud av voem. The Chinuch further connects honoring one's parents with appreciating Hakadosh Baruch Hu. "Ukesheyikba zos hamitzva benafsho yaaleh mimenahlehakir tovas Hakel Baruch Hu."
The Medrash Rabbah (Perek 10) explains that the proper expression of gratitude and thankfulness required that the first three makos be performed by Aharon instead of Moshe Rabbeinu. Moshe, who had been saved by water and dirt was unable to actively participate in these plagues.
How are we to understand this sense of hakoras hatov? Surely, the water and dirt did not go out of their way to aid Moshe Rabbeinu. Inanimate objects do not need, and cannot appreciate our gratitude.
We often measure our obligation of hakoras hatov from the perspective of the one who performed the act of chessed. We ask ourselves, how far did he go out of his way to help me? Will he appreciate my thankfulness?
The inability of Moshe Rabbeinu to participate in the initial makos teaches us that we must also view hakoras hatov from the viewpoint of the beneficiary. The mere fact that Moshe Rabbeinu benefitted from the water and dirt elicited an overwhelming sense of gratitude.
In this sense, Gemora Brachos (58b) contrasts the Oreach Tov and the Oreach Ra. Wheras the ungrateful guest minimizes his need to express gratitude, claiming, "kol toreach shetorach baal habayis zeh, lo tarach elah bishvil ishto uvanav," that the baal habayis exerted little additional effort on the guests behalf, the appreciative guest views any benefit that he received as though it was exclusively for him.
The Gra explains that each of us is an oreach in this world which Hashem created. One could selfishly feel that Hashem created little exclusively for him. How difficult was it for Hashem to provide me with a measure of good. True hakoras hatov, however, demands that each of us, as an oreach tov, view all chasdei Hashem as though bishvili nivra haolam, they were performed exclusively for me.
If the Torah insists that we acknowledge benefit from water and dirt, how much more so must we be constantly mindful of the gratitude our fellow man and ultimately that of Hakadosh Baruch Hu.