Many people don't enjoy food that is "too sweet." But some appreciate even very sweet foods and enjoy them immensely. This is a mashal describing the hardships of this world. Challenges are sweet because lots of good comes from them, but most people can’t appreciate this level of sweetness. At least let us believe that even when facing difficulties, they are for our benefit.
When we don't understand how something is good, the benefits are even better. It is so good that it is beyond human perception. The time will come when we will discover the good in all situations.
Rebbe Moshe Kobriner zt'l (quoted in Yesod HaAvodah, ג"נ קודש מכתבי) writes, "One must believe that everything that occurs is from Hashem Who is good to all, and it is certainly for man's good. And when he doesn't understand how it is for his good, he should believe it is an even greater favor for man."
The Tanya (Igeres HaKodesh 11) writes:
