Christians should be the most joyful people in the world. Our receiving of the Gospel. Our hope found only in Christ Jesus. Our joy that will be complete when we are finally in His presence. But I do believe Christians should be joyful even in this imperfect world.
That said, there are exceptions to that joy. In other words, what causes God grief? What causes Him disappointment? The Bible makes it clear that sin is the most responsible. My sin. Your sin.
The rebellion of man went so far as to cause God to grieve. His heart was filled with pain (Genesis 6). And God destroyed everything but the ark and creation inside. You and I know the story. And yet I wonder if it really changes us.
Richard Foster writes of
The Prayer of Tears. When we understand our sinfulness, what Christ Jesus had to do to redeem our sin, and our responsibility as followers of Christ, a humbleness that can't be explained becomes reality. The Church Fathers believed in an acknowledgment of sin that led to deep sorrow and weeping. Consider who many call the weeping prophet - Jeremiah.
...let your tears flow like a river day and night; give yourself no relief, your eyes no rest. (Lamentations 2:18) The Apostle Paul wrote,
"What a wretched man I am! Who will rescue me from this body of death?" (Romans 7:24) These are just two of many Biblical examples.
As the Psalmist declares
The sacrifices of God are a broken spirit; a broken and contrite heart, O God, you will not despise. (51:17)
Does your sin break your heart? It breaks the heart of God!