From the perspective of the Dharma, there are truths to be discovered in the workings of our mind, that when realized lead to the lessening and fading away of psychological tensions. Eventually, one is not drawn into those workings of the mind and could be said to be liberated from them. That is the promise of the Satipatthana Sutta.
But before that even begins to happen, the meditator needs to explore the mental processes that he is engaged in. When he experiences ill will, for instance, he knows that his mind keeps entertaining thoughts of revenge, that he feels malice toward someone else, and that he wishes that person harm, failure, and loss. Ill will is not shaken off easily, but he tries all sorts of strategies to get it to go away, practicing aversion toward his ill will, tying the knot tighter and tighter. This aversion to his ill will, which is just another manifestation of it, can become known as an obstacle to investigating his ill will. Ill will is not a hindrance until it makes it impossible to become aware of itself.
Consider the mental process of craving for something pleasant to happen, such as spending time with someone you like, receiving something you want to have, or having a wish fulfilled. It probably won’t feel like a hindrance, even though it fits snugly in the list of the 5 hindrances mentioned in the Satipatthana Sutta. But then you meditate with this craving occupying your thoughts and find it is not so pleasant to be obsessed, to sit still and feel excited, to feel as though you must rid yourself of this sense pleasure when it is exactly what you want right now. Being honest with yourself about this experience of craving is not a hindrance, but rather a way to gain greater self-knowledge and insight. If you sit longer with the particular craving and go through all the mental postures and attitudes you have about it, you may find that the craving is not getting in the way of your investigation. So, when is craving a hindrance?
It is actually subtle, hard to see, difficult to pinpoint. It is when there is enough and a thirst for more at the same time. This hindrance takes you away from looking into and exploring craving – it turns you around in another direction. We could call such hindrances detours that arise to make sure we don’t wake up and take a closer look at ourselves.