Obsession for some toys - why?

A part of kids earlier life is spent with the toys. Some of the toys like soft toys become there so hard favorite that they brush with them, walk with them, drink with them and sleep with them and so on. As a parent, I think that there should be some favorite toys of a kid, so that if the toddler becomes sad or cry, then it should  make him relaxed and soothe her. In the malls or airports we could see small kids carrying their toys mostly soft toys without which they cannot spend a single minute. When elder daughter was small she used to play with a small yellow chicken always. Even if we go to market, we had to carry it. No body else can even touch it. This continued till she was 3 1/2 years. So there are some things that kids also become obsessed to. If somehow the toy gets misplaced, then it used to be search time for everybody. Even if, I put it in front of the dryer, till the time it comes out, smiling to her I would say that your little chicken is taking bath.

    So it is nature of human beings to get attached to some things, in spite of the fact that these things are not talking and cannot show any emotions in response to our emotions.