When people get taken over by the ego to such an extent, there is nothing else in their mind except the ego. They can no longer feel or sense their humanity - what they share with other human beings, or even with other life forms on the planet. They are so identified with concepts in their minds that other human beings become concepts as well.
In this life, we have to make many choices. Some are very important choices. Some are not. Many of our choices are between good and evil. The choices we make, however, determine to a large extent our happiness or our unhappiness, because we have to live with the consequences of our choices.
To such an extent does nature delight and abound in variety that among her trees there is not one plant to be found which is exactly like another; and not only among the plants, but among the boughs, the leaves and the fruits, you will not find one which is exactly similar to another.