Sneezing and Yawning
Abu Hurayrah RA said: "The Prophet said, 'Allah loves the sneeze and dislikes the yawn. When someone sneezes and then praises Allah, it is a duty for every muslim who hears him to say, "May Allah have mercy on you." As for the yawn, it is from Satan, so one should repress it as much as possible. When a man says, "Haw!" Satan laughs at him."