Leaving my Shadow

In psychological studies, it is believed that no two person are exactly the same or alike. Even identical twins have different personalities be it skill or talent. they say every individual is unique and has his/her own identity. then how come we have the shadow of others?

Even today, in our modern society, this practice that I call "Shadowing" still exists. In the stable mind of every individual this practice cannot be removed. I too, had experience this.