Do you have an 'impossible dream'?

That’s what I call something you want, but can never have. My impossible dream is to be the first to explore a new earthlike planet. I know it’s kind of juvenile, but to me it would be very exciting to be the first one to step foot on an unknown (but liveable of course) planet. Think of the wonders. Anyway so am I unique in this? Does everyone want something they cannot have?