Notice that I said "when". For everyone, it's gonna be when and not if. Sometimes a person can get so lost that they feel like they're surrounded by darkness. Whether it's self-inflicted or not does not matter.
Notice I used the word "seek". That denotes that the person must actively do something to find light. One cannot sit around in despair, fear, unhappiness, or disappointment and just expect something to come along and change things. That person must SEEK light.
And, it doesn't take a genius to know what light is. Light warms the soul, elevates the heart, causes a smile to stretch out. Light reassures, uplifts, and causes us to want to spread the light to others.
We all know what it is. What we don't all know is how to find it. A lot of us tumbling around on this earth didn't have anyone to show us how to find light. A sad truth, yes, but guess what? That doesn't matter! The mere fact that one knows WHAT light is, means that one CAN find it!
So, what is the difference between those who replace darkness with light and those who don't?
Action. They actively seek the light.
And, anyone can do it. No matter what. Anyone can seek the light and find it.