Always for the Best

When something painful happens, Chazal still tell us to bless Hashem for the bad as we do for the good, and a Gemara in Berachos says to do it with simcha. How can anyone be happy while saying Dayan HaEmes? And in Ki Sisa, what did Hashem actually answer when Moshe asked why the righteous suffer, with the words "you will see My back"? Rashi's wording on that simcha opens the door. Rav Shach once told what everyone asked him as a young chassan with no house promised, and how his answer looked years later.