Many of us have some salt with our meals. Table salt is made up of both sodium and chloride. By itself, sodium is a deadly poison, and so is chloride. Put them together, and you have table salt. Salt flavors food, and a certain amount of salt is necessary for health and life. We cannot live without some salt in our systems. God can take things that are bad and put them in the crucible of His wisdom and love. He works all things together for good, and He gives us the glorious, wonderful promise that He will do so.
Now do not take this one short phrase "all things work together for good" out of context. It does not include everyone, only those who love God, and it is only true in relation to God's purpose in making us more like Jesus. And that does not happen because of bad things, but only when we love God and trust Him even when bad things happen.
What, then, is the good? It is defined for us, initially at least, in v. 29, one of the forgotten verses of scripture: “because those whom he foreknew he also predestined to be conformed to the image of his Son, that his Son would be the firstborn among many brothers and sisters”. The good is not our comfort, wealth, or health. It is conformity to Christ! This good is then fully defined in the next verse: “And those he predestined, he also called; and those he called, he also justified; and those he justified, he also glorified”. Ultimately, all things work together to bring each Christian into conformity to Christ, to bring each Christian to glory.
The plan of God is that we become like Jesus and those bad things give us an opportunity to overcome, to walk in love, and to grow into more Christ-likeness. But bad things do not make us more like Christ. It is only when we turn to the Lord (even in the midst of trouble) and allow Him to work in us, that we are transformed into being more like Him.
So those challenges that you are faced with, those circumstances that have you weary from worry, those relationships that you've been betrayed in, that job situation that has caused you major pains, those children that have you beyond stressed…. Is all good because it's for your good and God gets all the glory!