On every thorn, delightful wisdom grows, In every rill a sweet instruction flows.

However you understand why hard things happen, nobody is obliged to be grateful for one or to treat their suffering as a lesson arranged for their benefit. What can be said is that hard passages tend to hold information available nowhere else, about your own limits, about who shows up, about what you can do without. The wisdom is not compensation for the pain, and it can be gathered slowly, long after the worst has passed.

If you are in a rough stretch, you owe it no gratitude at all. Later, when there is room, ask what it taught you and keep only what is genuinely useful.