The beauty of most religions is a faith that there is much more than this life to look forward to experience. Every good and bad time here in mortality can be worth much more than what currently can be imagined. For Christians, this idea comes from the the Atonement and Resurrection of Jesus Christ where his mortal teachings are more than morals to live by because, "if in this life only we have hope in Christ, we are of all men most miserable" (1 Corinth. 15:19). How precious it can be to open the scriptures and read about Angels and Visions given to mortals as a witness that our person continues long after death. Joseph Smith said, "The things of God are of deep import; and time, and experience, and careful and ponderous and solemn thoughts can only find them out. Thy mind, O man! if thou wilt lead a soul unto salvation, must stretch as high as the utmost heavens, and search into and contemplate the darkest abyss, and the broad expanse of eternity—thou must commune with God" (History of the Church, 3:295). To live by faith is life eternal.
Despite the great blessings promised with faith, everyone experiences doubt. Perhaps all that we have been taught and come to believe is not true. The alternative is absolute darkness. Once our lives are over there will be nothing. It is a scary and sobering thought. While Joseph Smith discussed a vision he had of seeing family and friends rise from the graves on the day of resurrection to once again meet and hug them, he said, "More painful to me are the thoughts of annihilation than death. If I have no expectation of seeing my father, mother, brothers, sisters and friends again, my heart would burst in a moment, and I should go down to my grave." (Teachings of the Prophet Joseph Smith, p. 295). It is hard to imagine living with the idea that first we are here conscious of existence and then some day we are not.
God is what makes life worth living. Atheists might contend that meaning can be found without religious beliefs, but such is considered for those with beliefs greater than the here and now shallow and unproductive. They are not wrong that there is pain, suffering, and death that religion has inspired. Hanging on to those facts ignores the greatness and human dignity that accompanies and even surpases the negatives. A pound of flesh when beliefs are at the most illuminating becomes beautiful and of priceless worth. That people do not live up to the ideals taught is not the fault of the ideals of faith. Human nature of good and evil is as part of every person's life as the eventuality of death and taxes. To give up on it because of faults is short sighted and nihilistic.
Lehi argues in 2 Nephi:11-13 for the existence of God by the fact that something exists at all:
"11 For it must needs be, that there is an opposition in all things. If not so, my firstborn in the wilderness, righteousness could not be brought to pass, neither wickedness, neither holiness nor misery, neither good nor bad. Wherefore, all things must needs be a compound in one; wherefore, if it should be one body it must needs remain as dead, having no life neither death, nor corruption nor incorruption, happiness nor misery, neither sense nor insensibility.
12 Wherefore, it must needs have been created for a thing of naught; wherefore there would have been no purpose in the end of its creation. Wherefore, this thing must needs destroy the wisdom of God and his eternal purposes, and also the power, and the mercy, and the justice of God.
13 And if ye shall say there is no law, ye shall also say there is no sin. If ye shall say there is no sin, ye shall also say there is no righteousness. And if there be no righteousness there be no happiness. And if there be no righteousness nor happiness there be no punishment nor misery. And if these things are not there is no God. And if there is no God we are not, neither the earth; for there could have been no creation of things, neither to act nor to be acted upon; wherefore, all things must have vanished away."
As an unconventional, and somewhat out of context, interpretation of this scripture it can be said that without the belief in God there can be nothing. We come and go like a quick sparkle and are left without hope. That cannot be a pleasant way to live, although more people than ever seem to desire it rather than embrace a loving God with plans for eternal salvation. They may deny it, but seems more of a justification for living moral free by faking it as facing the truth.
Getting more personal, I have fainted twice in my life. Each time I had a sense of it coming and tried to avoid it without success. When I woke up there was disorientation followed by existential fear. Pondering those episodes brings confusion as I think what would happen if I never gained consciousness. Nothing mattered because for a very short time there was nothing other than eternal darkness. It would be a fate worse than outer darkness where even then, "there is weeping, and wailing, and gnashing of teeth" (D&C 133:73). To doubt the Love of God is tortuous that no amount of scientific knowledge can compensate.
When I was younger and first developed a testimony of God and the Church on my own, I pleaded in prayer that I too could see an angel like the prophets of old. Of course, I was never blessed with the chance. A great sadness in my religious life is lacking the experience of visions and undeniable miracles. Hearing stories of people who see relatives who have passed on, or rebuked demons, or healed from incurable conditions is reassuring. Despite wishing for that in my own life, my faith comes from other sources that provide no proof of a post-mortality. There is the love of Scriptures, prayers answered, comfort felt, examples from great people, and a knowledge gained that living the commandments is of great worth. Sometimes the mundane spiritual evidence is enough light to pierce the darkness. Sometimes those are too easily forgotten with a desire to be sure rather than assured.