I suppose that if a problem is easy to solve that it isn't even a problem. Just solve it and be done with it. A problem like that is more like a decision than a problem.
We all have bigger problems than that, though. We all struggle at times to solve what feels like an unsolvable problems. Some problems truly can't be solved, and must then be managed. How can we tell the difference?
We need to ponder the possibilities. We need to change the problem into a goal and figure out how to bring that about. The difficulty is like a framework for building something we haven't thought of before. The problem stands there, a form waiting to redirect our notions of what is possible.
Tough or not, solvable or not, a problem creates a space for traction.
A problem you can't solve is give you room to grow.