The Zhuangzi begins with the fantastic story of a vast fish that becomes a vast bird, Peng, who ascends to an incredible height so as to travel a vast distance. It's not the beginning I would have chosen and it seems to demonstrate the textual 'mutilation' that Graham finds throughout the book. Nevertheless, it becomes a potent metaphor whereby Zhuangzi presents the heart of his philosophy.
Seeing Peng flying overhead, a tiny quail laughs and wonders why he bothers since all he has to do to fulfill his needs is to sail from tree to tree. We are not told how Peng views the quail, but were he to laugh at the smallness of his world, in this there would be no difference between them. Both would have failed to understand that one's completion is realized in simply occupying one's being irrespective of size or accomplishment. If the quail were able "to forget his own smallness and wander within it", Wang Fuzhi comments, then his fulfillment may very well have surpassed that of Peng.
I am making comparisons, but the whole point is that no such comparisons are compatible with a life freely wandering within the range of its own particular limitations. Completion is being who one is, not who one is not.
We are all Peng, just as we are all quail, for there is always something bigger than the big and smaller than the small. Size does not matter. Since your mind has probably already gone there, I might as well pursue it further and add: "It's not the size of the worm, but how it wiggles that matters."
Guo Xiang, as might be expected, takes it even further and tells us that no comparison is likewise possible between completion and incompletion. The quail laughs at Peng because its inability to freely wander within its limitations is one of those limitations. Thus, laughing is its completion. It is simply being what it is, a silly quail; nothing more is possible or required.
This is, I believe, entirely consistent with Zhuangzi's point of view, though it raises the thorny issue of free will. There is no doubt that Zhuangzi recognizes the acceptability of what cannot seem other than 'unacceptable', of the immutable givens of Nature, but he also always sees even this as an occasion for transcendence. His Confucius understands how that he cannot wander freely as can a 'Daoist', but in understanding and accepting this he in effect does just that. There is always the possibility of freely wandering, even in the face of one's inability to do so — one need only wander in that. The gate always yawns open and wide; we need only say, Yes.
The quail laughs at Peng, and we laugh at the quail, but it is only when we are able to laugh at ourselves that we begin to wander freely.
You can check out Scott's writings on Zhuangzi here.