Islam is all about kindness and reciprocating kindness with kindness. So, as we are encouraged to exchange gifts with Muslims and non-Muslims, we are allowed to receive them and thank them for it.

The Prophet (peace be upon him) always received gifts and exchanged gifts with his non-Muslim neighbors and dignitaries.

While he was on an expedition in Tabuk, he received an envoy from Heracles. While he was leaving, he apologized to him that since he was a traveler he could not host him or send him away with gifts.  On hearing the words of the Prophet (peace be upon him) `Uthman ibn `Affan, the eminent companion, presented a valuable robe as a gift to him.

This incident shows how Islam promotes nobility and civility as the highest standards to aspire to while interacting with all people, regardless of religious or ethnic or racial differences.