question #3 Sahih al-Bukhari 6221, Book 78, Hadith 245 : What can be learned about the Prophet’s (ﷺ) approach to teaching manners and gratitude from this incident?

Two men sneezed before the Prophet. The Prophet (ﷺ) said to one of them, “May Allah bestow His Mercy
on you,” but he did not say that to the other. On being asked (why), the Prophet (ﷺ) said, “That one
praised Allah (at the time of sneezing), while the other did not praise Allah.”