Then how is one not to make oneself unhappy? How is one to live without suffering? By simply observing without reacting: Instead of trying to keep one experience and to avoid another, to pull this close, to push that away, one simply examines every phenomenon objectively, with equanimity, with a balanced mind.
This sounds simple enough, but what are we to do when we sit to mediate for an hour, and after ten minutes feel a pain in the knee? At once we start hating the pain, wanting the pain to go away. But it does not go away; instead, the more we hate it, the stronger it becomes. The physical pain becomes a mental pain, causing great anguish.
If we can learn for one moment just to observe the physical pain; if even temporarily we can emerge from the illusion that it is our pain, that we feel pain; if we can examine the sensation objectively like a doctor examining someone else's pain, then we see that the pain itself is changing. It does not remain forever; every moment it changes, passes away, starts again, changes again.
When we understand this by personal experience, we find that the pain can no longer overwhelm and control us. Perhaps it goes away quickly, perhaps not, but it does not matter. We do not suffer from the pain any more because we can observe it with detachment.
One of the easiest ways to apply this is with an itching head. Almost everyone experiences this during meditation and the impulse is just to give in and scratch it. I recommend that you not do this. Be faithful to the principle of still meditation and just let the itch be what it is. Usually it will fade in a few minutes. But we will never experience this if we are determined to have instant gratification no matter what.
After we've practiced observing physical pain in this way, we can then apply the practice to emotional pain. That's a bit harder because we tend to let emotional pain interfere with our observer consciousness. But with practice, you can do it. When we accept any kind of pain without judgment, we alleviate our suffering and experience true equanimity.