Daily Hakarat HaTov#4

The Midrash equates the sin of ingratitude with fundamental theological denial (kefira b'Ikar) of Hashem. One who is ungrateful towards his fellow man is ultimately ungrateful towards the Almighty as well. One who is an ingrate to his boss, his friends, his spouse, his parents, and his neighbor will eventually come to deny the favors of the Hashem.-Rabbi Yissocher Frand,Ki Tavo