The following quote is taken from 'The Pocket Thich Nhat Hanh' (click)
published by Shambhala Pocket Classics:
CONCENTRATION
"Joy and happiness are born of concentration.
When you are having a cup of tea, the value of that experience depends on your concentration.
You have to drink the tea with 100 percent of your being.
The true pleasure is experienced in the concentration.
When you walk and you are 100 percent concentrated,
the joy you get from the steps you are taking is much greater than
the joy you would get without concentration.
You have to invest 100 percent of your body and mind in the act of walking.
Then you will experience that being alive and taking steps on this planet are miraculous things."