One definition of this kind of complete happiness is, "The full use of your God-given talents and abilities along the lines of excellence." So the ancient Greeks and Romans said. Successful athletes in the arena, with millions watching, have a taste of glory we can easily imagine; which is why we watch, and why some pay thousands for tickets to see them in the flesh. When your beloved team is losing terribly but struggles through the pain and won't give up; then reverses their fortunes by agonizing, extreme, even super-human effort, and achieves victory... it's like a journey from death to life.
All of us at some time in our lives have dreamed of great wealth, the power to right wrongs and dispense justice, along with the love of our nation and the world, have we not? This is what awaits us in heaven. Scripture describes heaven as a place of no darkness or pain, no strife or fear; a place of eternal life, pleasure and joy beyond all human understanding, with "...power and riches and wisdom and strength and honor and glory..." (Revelation 5:12).
It's pretty clear that this world as we know it can never deliver anything close to real glory days. Earth is short of basic necessities, which are just a start. We don't live on bread alone, but also must have many other intangibles such as love, friendship, respect, and spiritual fulfillment; the Holy Spirit. An abundance of spirit can make us very grateful for all the good things in life, and create a longing for worlds beyond. There are many worlds much better than earth.
We aren't aware of it, but death is ever-present in this life. It comes in many forms, killing hope, love, innocence, and our dreams. We call it 'change' because we must, in order to live our lives with some modicum of pleasure. Death permeates our relationships on every level. We will be liberated from death in a time to come, and this alone is a joy beyond all other joys.
The world is filled with injustice, and it's in our DNA to thirst for justice. Even horses and other animals understand justice and fairness, and will rebel at injustice, as any competent animal trainer will tell you. On earth it's all too easy to be cheated, defrauded, and abused physically and emotionally by others who have little or no conscience. Sometimes we're victimized by people we thought were our friends. Often there's not enough proof to use the law for justice, or the law is too expensive or weak. We then just have to sit there and take it. It hurts.
Jesus said, "Blessed are those who hunger and thirst for justice, for they will be filled." (Matthew 5:6). Have faith. Jesus and His heavenly host will save all people of goodwill. We will be redeemed and made more than whole. Either in the next world, or a future earth.
The Pearly Gates