"When we attach ourselves to impermanent objects - sensations, thoughts, feelings, people, things - we are always left with the stress and grief of loss, because everything around us is always changing; it is always being pulled beyond our reach. Our grasping, our fighting against impermanence, results in loss and the suffering that comes with trying to hold on to the constantly changing reality. It's rather like trying to play tug-of-war with a much stronger opponent; we begin to lose, as we always will, we can choose to let go or to hold on and receive the "rope buns" of attachment. The survival instinct tells us to hold on; the Buddha urges us to let go."
"All unpleasant thoughts, feelings, and sensations are impermanent; trying to push them away is futile and results in stress, anger, and suffering. It's as if with our aversion we created a dam in the flow of experience. Rather than letting impermanence do its job, we block the passing of pain. We do this in a variety of ways - through suppression, avoidance ignoring self-medicating, or hardening the heart and closing down to life. Again, as a survival instinct aversion is necessary - we have to hate pain to survive - but it doesn't leave us with much freedom or happiness. when it comes to aversion, the survival-based life is a life of fear and loathing. Our instincts tell us to hate pain and try to get rid of it; the Buddha urges us to meet pain with mercy and compassion."
"We can all concede... that everything is impermanent... [T]he evolved human condition has resulted in a brain that creates a self. The sense of being a permanent fixed identity - a self - is a construction of the mind/body. Each one of us is a constantly evolving and unfolding process, not a fixed identity. This aspect of reality - that is, our own changing nature - seems to be at odds with the human survival instinct, so the mind creates a fixed identity that takes everything personally and clings to the notion of "I", "me", and "mind". But this solution is based on ignorance and a lack of investigation. Believing in a permanent self is like believing in a permanent rainbow. We all know that rainbows are temporary optical illusions based on the factors of sunlight, moisture, and heat. The environment creates each rainbow like a mind creates a self. Both creations are relatively real, in that we can genuinely experience them temporarily, but just as the factors that create the illusion (whether rainbow or self) arose, so will they also pass. There is no permanent self; there is no permanent rainbow. It is not true to say that there is no self at all or that everything is empty or illusory, but it is true that everything is constantly changing and that there is no solid, permanent, unchanging self within the process that is life. Everything and everyone is an unfolding process."
Excerpts from "Wide Awake", by Noah Levine.
This was one of the most insightful and best explained pieces I've read in a long time.