I don't know about anyone else, but space has always simultaneously fascinated me and freaked me out. The idea of what's out there (and what could be out there) makes my mind spin. I mean, how are we supposed to even fathom something that's infinite? It's just impossible.
But if there's any comfort to be found, it's in knowing that our solar system is at least somewhat understood by scientists, and we have a pretty good idea of what's out there in the way of planets. My personal favorite? Saturn.