Happiness on this earth makes happiness in the next less attractive. If happiness in the next looses its appeal what is the need of the priests, the pastors, the Imans who promise it? The clergy offer grand promises and if you feel insecure, inadequate, lonely, these promises are very appealing.
True spirituality is nourishment in the here and now, not in the hereafter. A spiritual person has no need of clergy making false promises and threatening with false punishments. Peace comes from the liberation from supersitions and delusions. Peace comes from being at one with cosmic consciousness.
Jesus told us to be aware of false prophets. An irrevernt saying in Buddhism is "If you meet the Buddha on the road, kill him." And being in touch in our hearts with the Tao relieves our fears, our lonliness, our depression, our anger, and we achieve serenity here on earth as it is in heaven.