As time goes by, we build an armor around ourselves. A shell, so to say.
To protect us from the darkness of this world. To let us live every day; to not bury us with the hardships. It's a protective element, and almost all of us have developed it to some extent.
Yet, it's incredibly easy to build it too thick, to develop a level of apathy. To not feel; to not let things through. To become numb, block all incoming signal. This may happen both unintentionally and intentionally. But it's always absolute in its effects.
When you reach that point, you start depriving yourself of your own humanity. It starts to fade away, as you move forward into the grayness of your own void.
Let it through, let it in. Let it break you. Let yourself fall.
Don't avoid darkness, you'll never see light then.