In life we meet many Christians who try to fake happiness. They feel commanded to be happy and so they go around with a smile on their face when they are clearly miserable. It is as if it is a sin to be sad.
You see they miss the fact that joy (which is commanded) and happiness (which is not commanded) are very different. You see joy is at a much deeper level and it is a state of character and faith more than an emotion.
And the issue is greater that we are commanded to morn with those who morn. You see we can be expected and godly to be unhappy!
We can have joy and morn. God's commandments are difficult and we always fall short and have a sympathetic high priest in Jesus.
Scripture challenges us always. It defines things as God sees them rather than as we see things. Many things we see as exactly the same God sees differently. Many things we see as completely different God sees as interconnected.
It is always that we are too small and too nearsighted to see all the realities. That is why we need for God to tell us of the realities and later we usually figure out why God was right all along for ourselves.