Wabi-sabi 侘び寂び（わびさび）is embracing the beauty found in simplicity, and things that are sometimes flawed, damaged, or incomplete. It’s an aesthetic philosophy originally derived from Zen Buddhism.
The concept of 侘び寂び is said to be difficult to explain, much like it’s difficult if not impossible to explain the taste of something (without describing the flavor of another item to explain the taste). It’s based on the acceptance of asymmetry, irregularity, and simplicity found in natural objects (and in the process of creating something). It’s realizing that nothing lasts, nothing is perfect, and nothing is really ever finished, but more than that, it evokes a sense of spiritual calmness.
Japanese pottery often incorporates 侘び寂び, and in Japanese tea ceremonies （茶の湯（ちゃのゆ）、（茶道（さどう or ちゃどう） or sometimes referred to as simply a （茶会（ちゃかい) literally meaning “tea meeting”, pottery is used that has a simple or rustic appearance. The colors are often unrefined and the shape is not quite symmetrical. The point behind this is so the participants can try to realize the hidden beauty that is in everything, no matter how simple, natural, or “flawed”.
Here are some examples of 茶碗（ちゃわん） that have characteristics of 侘び寂び.
A popular style of pottery that incorporates this concept is called Hagi ware（萩焼（はぎやき）. The bottom of the tea bowls are purposefully nicked as a type of signature.
Instead of stressing over finer details that are unnecessary and may actually take away from the beauty in something, for instance with art, it should be natural, incomparable, and bring us back to a less stressful mindset.
The concept of wabi-sabi doesn’t end with art though, it’s a mindset for everything.