Because it is inherent in most of us to want to be noticed. Haven't you ever seen the little child pleading for its mother or father to "Look at me," and feeling ignored when there is little or no response. When we're older we're generally after the same sort of attention. But now we want it from more people. You might say we want to be 'famous.'
We all think we're the centre of the universe. It's what happens to us that is most important in most of our lives. It's a me, Me ME! thing. Can't be helped. We're only human, after all.
We strive to reinforce this by wanting people to know about us - me no less than the rest. It's acclaim, recognition, celebrity.
Whether we'll ever be happy if we get that recognition is something else again...