They who have no central purpose in their life fall an easy prey to petty worries, fears, troubles, and self-pitying, all of which are indications of weakness, which lead, just as surely as deliberately planned sins (though by a different route), to failure, unhappiness, and loss, for weakness cannot persist in a power evolving universe.
Unfulfilled dreams, ongoing relational tension, the loss of friendships, a hard marriage, rebellious teenagers, the death of loved ones, remaining sinful patterns - whatever it is for you - live long enough, lose enough, suffer enough, and the idealism of youth fades, leaving behind the reality of life in a broken world as a broken person.
The principles of gain through loss, of joy through sorrow, of getting by giving, of fulfillment by laying down, of life out of death is what the Bible teaches, and the people who have believed it enough to live it out in simple, humble, day-by-day practice are people who have found the gain, the joy, the getting, the fulfillment, the life.