We can lose the stuff of life that may from time to time put a smile on the face, but we can never lose Christ, the source of true joy (see Habakkuk 3:17-18 for a smiliar thought). If we are not content with Christ, we will have no defense against the depression or fear caused by the norms of life. But if our delight is truly in the Lord, it is absolutely impossible to be disappointed, because He will always give us the desires of our heart. He will give us Himself (Psalm 37:4).
Michael P. V. Barrett, God's Unfailing Purpose: The Message of Daniel, (Greenville: Ambassador Emerald International, 2003), 160-61.