An archer competing for a clay vessel shoots effortlessly, his or her skill and concentration unimpeded. If the prize is changed to a brass ornament, the hands begin to shake. If it is changed to gold, he or she squints as if going blind. The abilities do not deteriorate, but belief in them does, as he or she allows the supposed value of an external reward to cloud the vision.
ZhuangziAll existing things are really one. We regard those that are beautiful and rare as valuable, and those that are ugly as foul and rotten. The foul and rotten may come to be transformed into what is rare and valuable, and the rare and valuable into what is foul and rotten.
Zhuangzi