Q: Why did the Creator make His creation feel deficient upon receiving?
A: He did so in order to awaken in us the need to change our intent to receive into intent to give. Only to those whom the Creator wants near Him does He send the sensation that they receive from Him. In order to feel it, one must first rise to the degree of the revelation of the Creator, to feel Him as the Giver. Man can ask for that revelation because it is for the purpose of correction, not for pleasure.
The host offers his guest food and drink. All the guest actually wants is the food, but along with his desire (vessel) and the future pleasure (the Light), there is yet another sensation – the presence of the host, the giver. Because of that, he feels himself as a receiver, a taker. That sensation is so unpleasant that it overshadows the pleasure of eating the food.