Every time we take a step towards something better, we learn more than we knew before. The revelation of this knowledge will always include increased awareness of what is incomplete or incorrect in ourselves, because we are not yet perfect.
When you turn a light on in a dark room, you see things you didn't see before. The light does not make things good or bad. Rather, it reveals details that were not previously known, and these details reveal what is good and what is bad.
In scriptural vernacular, every time light is dispensed, it reveals darkness. You get to decide how you react to that revelation.
It is very unusual for humans to react with joy to the opportunity to know more about the darkness inside themselves:
19 And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil.
20 For every one that doeth evil hateth the light, neither cometh to the light, lest his deeds should be reproved.
21 But he that doeth truth cometh to the light, that his deeds may be made manifest, that they are wrought in God. (John 3)
If you truly want to improve—if you truly want greater joy and happiness—you must also develop a love of correction. The path to greater joy and happiness will always include a greater understanding of what you lack.
Unfortunately, almost all people will turn away from opportunities to learn more about themselves. They do not want to be good, which requires change. Instead, they want to feel good, which is all about avoiding evidence that they aren’t actually good.
No one would proclaim that they hate improvement. Instead, the way this attitude manifests itself is through one’s feelings and actions. People tend to hate having their choices, actions, beliefs, and words questioned. They hate when others point out something better than what they do. They want to fit in. They want to please others. They don’t want to be different. They don’t want to fight conventional wisdom. They don’t want to deny their base desires.
When you make good decisions, you are choosing to fight against human nature. When you decide to improve, you should be prepared for the opposition that will come. Before, during, and after good decisions, you will be subjected to powerful forces within and without that will challenge your decision.
Most do not want to know more than they do. They prefer to remain in their previous blindness. They respond to the gift of light by squinting their eyes shut. They decide against the light because they do not like the evil it reveals in them. After this rejection in their hearts, they create reasons in their minds to justify their decision. These reasons rarely make sense. In fact, they typically are so inconsistent and illogical that even a child could pull them apart. But they don't see it themselves, because in their embrace of darkness they have inadvertently lost a portion of the light they previously possessed.
Some few love the light. They love when they are shown how they can be better. Some of them react this way for a while, perhaps for a few iterations of greater light. Very, very few will endure everything God shows them, step by step, until there is no darkness left. When there is no darkness left, you have eradicated all the barriers to receiving God's light in you. It is only at this point that your eye is single to the glory of God. It is only at this point that you have withheld nothing from God. It is only in this state that you can overcome all things and receive all things that God offers. It is only through this path that you can encounter what we all seek deep down inside: eternal happiness.
We can choose how we act, think, feel, and believe. We can't choose where those choices lead us. Where those choices lead us is predetermined and fixed by eternal law declared before this world was created. Almost everyone will receive far less than what they desire, because they are unwilling to walk the path that leads to the fulfillment of those desires.
There is no fault in not knowing the way. However, everything needed has been provided in and through Christ who said he was the way. The fault comes in turning away from the way when it is offered to you because you think you know better than God. You think that it isn't really necessary to submit to his wisdom, mercy, and love:
O that cunning plan of the evil one! O the vainness, and the frailties, and the foolishness of men! When they are learned they think they are wise, and they hearken not unto the counsel of God, for they set it aside, supposing they know of themselves, wherefore, their wisdom is foolishness and it profiteth them not. And they shall perish. (2 Nephi 9:28)
Perhaps you reject the gift because it comes in a wrapper that doesn't fit your preconceived notions. Regardless, for the vast majority of humankind, the judgment will contain the phrase: “you received what you were willing to receive, though far greater things were offered you. This is the situation you have chosen.”
It is upon this hinge that all of salvation rests: how will you respond when the light shows the darkness that remains in you?
As long as someone is living according to the light they previously received, there is no way of knowing ahead of time how someone will react to greater light. The only way is to give it. This is part of the price paid by those with greater light. They continuously reach out knowing that almost all of the time their efforts will be rewarded with pain, hatred, and persecution from those they love. They do it anyway.