Meditation is a great opportunity to look within and see the prison we have made for our self by desiring what is not our self. It is a strange kind of darkness but a darkness, nevertheless, that keeps the light from coming in. In a way, it is a true picture of our incarnated life a life that will one day be filled with a great deal of suffering.
“Think that this body is like a plantain, a mirage in the hot season, watery foam, a phantom, a transformed body, the castle of a gandharva, an unfired brick, lightning, a picture drawn on water, a prisoner facing death, ripe fruit, a piece of meat, the warp on a loom which is about to end, and the ups and downs of a mortar. You should think that all created things are like poisonous food and that anything made is possessed of all worries” (Mahaparinirvana Sutra).
A great Buddhist teacher like Ajahn Chah (Phra Bodhiñāṇathera) might tell us that meditation is a time to see what's inside our cage: the cage of birth, aging, illness, and death. As we might guess, looking within is a difficult task for those of us who are used to accumulating desires. Yes, each desire keeps the light from penetrating the thick, impenetrable wall of our desires. Such people will attain nothing in their halfhearted search.
Beginners of meditation always believe that meditation is going to lead them to some profound vision. What is really at work here is their imagination, not profound gnosis. Meditation helps us to sober up from our last round of intoxicating desires. It reminds us that we are still in samsara; we're not going to escape it by having a good time!