When does Allah laugh? And what makes Him laugh?

The attribute of laughter for Allah, the Almighty, is one of the active, خبرية (khabariyyah) attributes, firmly established for Him, the Exalted, in a manner befitting Him, and it does not resemble the attributes of creation. This is based on His saying, the Almighty: ﴿There is nothing like unto Him, and He is the All-Hearing, the All-Seeing.﴾ Many evidences from the authentic Sunnah have been reported confirming this attribute, including the hadith of Abu Hurairah, may Allah be pleased with him: «Allah laughs at two men, one of whom kills the other, yet both enter Paradise,» and the hadith about the last person to exit Hellfire. Allah, the Almighty, laughs whenever He wills. The Sunnah mentions some instances when Allah laughs, including: the two men, one of whom kills the other, yet both enter Paradise; and three whom Allah loves and laughs at them (the mujahid, the one who stands in prayer at night, and the traveler who stayed up his night in worship); and His laughter at the action of the Ansari and his wife in honoring a guest.