When you prepare food, your sense of taste and smell are activated by the odours involved, and your mind starts to anticipate the enjoyment of the food. because even short preparation time, such as for a sandwich, means that your anticipation peaks, and then dissipates, you will never get the same satisfaction from eating something you have prepared.
The recipient receives, the food, their anticipation kicks in, and is satisfied almost immediately by consumption of the food, producing a far more satisfying sensation of enjoyment.