One of the important principles learned in Parshat וארא that is worth emphasizing, is the concept of הכרת הטוב, recognizing the good that is done to us. We learn this from the manner in which the plagues were done to the Egyptians. Moshe was not allowed to inflict those plagues that began in the water or in the sand. The water saved him when he was a baby and the sand allowed him to hide the Egyptian he killed. He needed to show gratitude even to inanimate objects.
This was to teach us a lesson in our relationship with Hashem and others. We must never forget the numerous acts of kindness that Hashem showers us with. Similarly, we must remember Chessed that has been done for us by our family and friends.
One of the worst traits is to be a כפוי טובה, an ingrate, who has the ugly attitude of, “What have you done for me lately?” while forgetting the kindnesses of the past.