Robyn Griggs Lawrence, author of Simply Imperfect: Revisiting the Wabi-Sabi House:
According to Japanese legend, a young man named Sen no Rikyu sought to learn the elaborate set of customs known as the Way of Tea. He went to tea-master Takeeno Joo, who tested the younger man by asking him to tend the garden. Rikyu cleaned up debris and raked the ground until it was perfect, then scrutinized the immaculate garden. Before presenting his work to the master, he shook a cherry tree, causing a few flowers to spill randomly onto the ground.
To this day, the Japanese revere Rikyu as one who understood to his very core a deep cultural thread known as wabi-sabi. Emerging in the 15th century as a reaction to the prevailing aesthetic of lavishness, ornamentation, and rich materials, wabi-sabi is the art of finding beauty in imperfection and profundity in earthiness, of revering authenticity above all.
Check out the Wikipedia article for more examples and some photos.