Psalm 23 says that David waked through the valley of the shadow of death. That doesn't sound like much fun. In fact, for many who are going through a difficult time, it begs the question, why do we need valleys? If God is good, couldn't He use His goodness and power to keep life fantastic for us at all time? Wouldn't a life of mountain tops be better?
Actually, that question itself is impossible. A land filled with mountain tops would be a flat valley. Mountaintops are made beautiful by the very fact that there are valleys. And depending on where you are, valleys are filled with foliage that cannot be appreciated from the mountaintop. Both experiences create a fuller experience of life.
For us to be dogmatic and assume all of life should head in a certain direction is an invalid conclusion because the beauty in life and the beauty in creation comes from the multidimensional terrain.
God didn't make this life a flatland. He made it a beautiful world of valleys and mountain tops. It's our job to trust Him through it all. As we trust Him, we can hunt for the beauty in the valleys and soak in the majesty of the mountain tops.