The apostle Paul does not say that all things are good, but he does say that all things work together for good.
The same counsel was given as revelation to Joseph Smith the Prophet in 1833:
"Search diligently, pray always, and be believing, and all things shall work together for your good, if ye walk uprightly and remember the covenant wherewith ye have covenanted one with another." - D&C 90:24
This counsel was repeated again a few months later:
"Therefore, let your hearts be comforted; for all things shall work together for good to them that walk uprightly, and to the sanctification of the church." - D&C 100:15
Let's say you get in your car, and it won't start. There are two ways you can look at the situation. You can say, "I knew it! It never fails. My plans always flop." Or you can say, "Well, it looks as though I can't leave right now. I'll go later when the car is fixed. In the meantime, I believe this change in plans is going to work out for my good. There is probably some reason I need to be at home today, so I'm going to enjoy my time here."
Paul also tells us in Romans 12:16 to readily adjust yourself to people or things.
"Be of the same mind one toward another. Mind not high things, but condescend to men of low estate. Be not wise in your own conceits."
The idea is that we must learn to become the kind of person who plans things but who doesn't fall apart if that plan doesn't work out. We must be willing to conform and to be humble at the same time.
The choice is ours. Any time we don't get what we want, our feelings will rise up and try to get us into self-pity and a negative attitude. Or we can adjust to the situation and go ahead and enjoy what God has for us no matter what happens.
One of the challenges we face as Latter-Day Saints is to find peace and comfort in the face of opposition. When we view trials and incendents that are uncomfortable it is natural for us to focus on the bad or the negative. We can find peace and comfort when we take the opportunity to see what we can learn from the situation or know that blessings do come in the face of trials.
The pathway to freedom from negativity begins when we face the problem without making excuses for it.