For humans, it has become, not anymore.

What do you mean? Negative is an attitude towards life, but a negative life is not good for people.

Like the sun, people need to shine.

Both the earth and human beings are shrouded in the brilliance of the sun, but in our feelings, we may never really feel the importance of the sun. Day after day, year after year, the sun rises and sets tirelessly, and the sunshine that hits us seems to never change.

You think so, but you think so is wrong. Sunlight is not only life itself, but also affects all this through its influence on the earth's ecology and biology. All these reasons come from the colorful sunshine, which has influenced the changes of the world and human society. For details, please see The Secret of the Rainbow.