Perhaps the most elemental obligation of Hachnassas orchim is to make a guest feel good about accepting the hospitality offered to him. He should be made to understand that he is the real benefactor - he enables the host to merit in the fulfillment of the mitzvah. Ralbag writes that this may be inferred from the verse, "My Masters, if now I have found favor in your sight, pass not by, I pray, form your servant" (Bereishis 18:3). In addition, the Midrash (Midrash rabbah, Vayikrah 34:10) says, "More than the host benefits the poor person, the poor person benefits the host."