Chapter 31, Part J - Chuang Tzu

"It may be applied to human relationships in the following ways. In the service of parents, it is love and filial piety; in the service of the ruler, it is loyalty and integrity; in festive wine drinking, it is merriment and joy; in periods of mourning, it is sadness and grief. In loyalty and integrity, service is the important thing; in festive drinking, merriment is the important thing; in periods of mourning, grief is the important thing; in the service of parents, their comfort is the important thing.

"In seeking to perform the finest kind of service, one does not always try to go about it in the same way. In assuring comfort in the serving of one's parents, one does not question the means to be employed. In seeking the merriment that comes with festive drinking, one does not fuss over what cups and dishes are to be selected. In expressing the grief that is appropriate to periods of mourning, one does not quibble over the exact ritual to be followed.
~ Burton Watson translation via Terebess Asia Online ~

Go here to read the introductory post to the chapters of the Book of Chuang Tzu.