One aspect of Mormon theology which I have found extremely helpful in understanding the human condition is that humans had pre-mortal existence.
It took me a while to understand why this was such a significant part of the account of the 'plan of salvation' - but I now perceive it has a vital role; because it enables the explanation that each person chose mortal life on earth - just as Jesus Christ chose to become incarnate as a Man.
By this account, we were not created (indifferent to our wishes) in this vale of tears; we are not thrown into life whether we want it or not, whether we like it or not - but our pre-mortal spirits chose to live on earth in physical bodies, and to undergo death - before returning to the presence of God.
The idea that we are all, without exception, volunteers in this life has the effect of transforming the perspective on the nature of the human condition; and dissolving many of the apparently intractable questions related to human suffering.
Because to inflict suffering upon a person who has been thrown into the world, willy-nilly, like it or not, is morally a very different matter from the sufferings undergone by a volunteer.
Supposing that the extreme physical and mental trials and training voluntarily undergone by special military forces, such as the Navy SEALs, were inflicted on all young men, and against their will... this would be torturing them, pure and simple. The fact of volunteering transforms the moral situation.
And, like special military forces; our voluntary consent to mortal human life was to the general process of life (including death), and to the objectives of that process of life, and not each specific one of life's trials - which were neither known, nor determined, in advance.
As Terryl Givens makes clear in his scholarly and thorough 2010 monograph When Souls Had Wings: Pre-Mortal Existence in Western Thought; the idea that humans had a pre-mortal existence is one that can be traced back to ancient times, perhaps through some specific Biblical texts, through some of the early Fathers of the church (probably including Origen and St Augustine) and right up to this day.
The idea of pre-mortal existence has been persistent and recurrent because of its great explanatory value - and from the fact that without pre-existence and the idea that we volunteered for incarnate morality, the Goodness of God becomes... well, if not impossible to explain, then at least a difficult, complex and often incomprehensible thing to explain.
Note added: I would add that mortal life is an experience, more than a test; and no matter how brief it may be - even if it ends in the womb - all mortal life includes the experience of death (death of the mortal body). Therefore, it seems that the experience of death is the minimum/basic reason for mortal, incarnate life.