"The crucible for silver and the furnace for gold, but the Lord tests the heart" (Proverbs 17:3).
My wife LOVES jewelry! I remember when we were just dating, I had asked her about what kind of jewelry she liked. She said that she liked silver, but that it had to real. The fake stuff, she explained to me, would give her a rash. Now I must tell you, that at first, I thought she was making the whole thing up just so that I would give her the "good stuff." But sure enough, she was right!
The value of precious metals is what further makes them desirable. The master of those metals would do whatever was necessary, not just to maintain, but to increase the value by testing the purity. This would be done by a process of melting and purging. All the impurities would wise and would be scraped off the top - all possible because of the increase in extreme heat.
God does similar with our hearts. It is more valuable to Him than precious metals, and He's most interested in the "good stuff", too. He will test the purity in the crucible of life. The process is sometimes intense, but the product is priceless.
Whatever you're going through right now that may seem so unfair, be sure to understand something. It's not that God is necessarily mad at you. He love you. So much, in fact, that He's willing to do whatever possible to bring out the stuff in you that needs to be removed, so that the integrity of your value increases! You are worth it!