For it must needs be, that there is an opposition in all things. If not so, my first-born in the wilderness, righteousness could not be brought to pass, neither wickedness, neither holiness nor misery, neither good nor bad. (2 Nephi 2:11)
If I want to get stronger, I need to go to the gym and lift weights. Not just lift weights, but push myself to lift more than my muscles are used to lifting, to the point of exhaustion. When strength training, what rep really matters the most? The last one. All the previous ones only served to wear your muscles down to the point of fatigue and exhaustion. Then when your will makes your body keep going despite that, somehow your body gets programmed: I'm going to make these muscles stronger!
I am learning that these same principles of athletic training apply to spiritual growth as well. How am I going to develop patience unless I am given situations when nothing I can do will make things immediately better? How can I strengthen my faith in God unless I pray and do the best I can despite the temptation to feel overwhelmed and discouraged? How can I come to love as God does, unless I forgive others, and bear with them in their shortcomings; as they do for me?
I could go on. But these insights help me to acknowledge God's hand not just in the blessings and good things of life, but also in the trials and difficulties. I know that God is my Father in Heaven, and that He loves me with a tenderness and care that far surpasses even my love and care for my own children. He is not mean, indifferent, or distant. Rather He feels our heartache, and cries with us our tears, and carries us when we have no strength. Why does He not fix the problem, or remove the pain, you ask? I can only suppose for the same reason why I do not solve all my children's problems, or give them everything they want; and why I make them do their chores and their homework before they play. I have been where they are, and I know where they need to go in order to be happy and successful in life.