For those who don't remain forever on a spiritual high here are a few thoughts from Elder Orson Pratt:
"But now having spoken so much about the benefits of this light, and how good it would be to be continually guided and instructed by the spirit of revelation, there is another thing connected with it which we perhaps do not all fully understand. Supposing a person were thus guided all the time, from waking in the morning until they retired to rest at night; and then when asleep if his dreams were given by the same spirit, and this should be the uninterrupted condition of an individual, I ask, where would be his trials? This would lead us to ask, Is it not absolutely necessary that God should in some measure, withhold even from those who walk before him in purity and integrity, a portion of his Spirit, that they may prove to themselves, their families and neighbors, and to the heavens whether they are full of integrity even in times when they have not so much of the Spirit to guide and influence them? I think that this is really necessary, consequently I do not know that we have any reason to complain of the darkness which occasionally hovers over the mind. I recollect that Lehi had a very great and important dream communicated to him, and his son Nephi had the same renewed to him. While Lehi was on his way to this country he dreamed that he wandered many hours in darkness; that there was a certain rod of iron, notwithstanding this darkness that seemed to gather around him, on which the old man leaned steadfastly. So great was the darkness that he was fearful he should lose his way if he let go the rod of iron; but he clung to it, and continued to wander on until, by and by, he was brought out into a large and spacious field, and he also was brought out to a place where it was lighter, and he saw a certain tree which bore very precious fruit. And he went forth and partook of the fruit of his tree, which was the most precious and desirable of any fruit that he had ever tasted; and it seemed to enlighten him and fill him with joy and happiness. Lehi was a good old man--a man who had been raised up as a great prophet in the midst of Jerusalem. He had prophesied in the midst of all that wickedness which surrounded the Jews; and they sought to take away his life, because of his prophecy. But not withstanding this gift of prophecy, and the gifts of the Spirit which he enjoyed, the Lord showed him by this dream that there would be seasons of darkness through which he would have to pass, and that even then there was a guide. If he did not all the time have the Spirit of God upon him to any great extent, there was the word of God, represented by an iron rod, to guide him; and if he would hold fast to that in his hours of darkness and trial, when everything seemed to go against him, and not sever himself therefrom, it would finally bring him where he could partake of the fruit of the precious tree--the Tree of Life. Consequently I am not so sure, that it is intended for men of God to enjoy all the time a great measure of his Spirit."
[Orson Pratt, November 24, 1872, in Journal of Discourses, Vol.15: 234-235].