In the west, just a few years back, there was a french hypnotist, Emile Coue; he happened to rediscover one of the basic laws of the human mind. He called it," The Law of reverse effect" - that is one of the oldest Sutras in Taoist and Zen thinking. Susan is talking about this law. Try to understand this law then his sayings will be simple to understand.
For example, if you don't feel sleepy what will you do? You will try to get into sleep - you will make efforts, you will do this and that, but what so ever you do will bring just the reverse, just that which you need will not come.
Just the opposite will happen, because any activity, any effort, is against sleep.
Sleep is a relaxation. You cannot bring it, you cannot do anything for it to happen. You cannot force it, you cannot will it - it is not a part of your will at all. It is moving into the unconscious, and your will is just a fragment of the conscious.
When you move into the unconscious, towards the depth, that fragment which is consciousness, that fragment which is will, is left on the surface. You cannot take your surface to the depth, you cannot take your circumference to the centre. So when you make efforts to go into sleep, it is a self destructive thing. You are doing something which will become just the opposite - you will become more awake. The only way to enter into sleep is not to do anything. If it is not coming, it is not coming. Wait..... don't do anything! otherwise you will push it further away and a distance will be created. Just wait on the pillow, put off the light, close your eyes, relax and wait. When ever it comes, it comes. You cannot bring it by any act or your will - will is against the unconscious.
And this happens in many things in life, just the opposite comes out of it. If you want to be silent, what will you do? because silence is just like sleep. You cannot force it. You can allow it to happen, it is a let go, but there is no way to work it out. What will you do if you want to be silent? If you do anything you will be less silent than ever.