Why do we want to be noticed?

Even though it's a slim chance that you'll meet this person, to you, the possibility of the reward outweighs the unlikeliness and the risk (risk = money spent).

The reason for wanting to meet an admired famous person, varies from one individual to the next. I'd say that if there is a consensus, basic reason, it comes down to survival. At our animalistic roots of motivation, we want companionship (of any kind) with someone whom we admire because in our own opinion, they could effect our lives/survival in a good way.

I've been an aspiring psychologist for nine years. Not trying to brag, just letting you know why I feel qualified to answer this. :P