Happy Thanksgiving! Even to you not in the United States!
One of my favorite little-known sayings of the Prophet Joseph Smith was recalled by President Brigham Young in 1869:
I recollect hearing the Prophet Joseph say, many times in his day, that no greater sin was ever committed on this earth than the sin of ingratitude. (Brigham Young, Address, 10 October 1869, Deseret News Weekly 18 [1 Dec. 1869]: 507, to be published in Teachings and Sayings of the Prophet Joseph Smith, forthcoming from the Joseph Smith Research Institute).