Some people are more sensitive to one color than others. Some can physically feel the affect of a color on them.
When you go through a meditation and stimulate the different chakras with visualizing a color, you can at this time see the effect a certain color has on you. You can also begin to understand how a color can have energy of its own when you visualize colors and feel them, trigger them, and stimulate the energy of different chakras.
Certain seasons display colors, and through that process, it may also activate feelings which your soul is most tied to. This color wave frequency comes from the Tao and with it, certain emotions may accompany that color, too; for example, love, peace, harmony, etc.
There are other mechanisms on the earth or in the environment which also stimulates similar responses within ones soul, just like color. For example, music, movement (such as dance, swimming, running, etc), some writings, and even certain foods. These are also forms of communication that come from the Tao and can connect and communicate with your soul.
Some of these are necessary for physical life, like food and movement, but they also provide a mechanism of feeding the basic spirit of a man or woman.
Do we need to be aware of these frequencies or interactions or energies from the Tao? No, not necessarily. But, it can help to improve life and enhance the quality of your life.