I think it is interesting and at times enjoy Sci-Fi and Fantasy literature / film because of it. I like having an active imagination. However, I understand the science around the likely hood of it. I really don't actively debate such.
As a novice writer I play with conceptualizing visitors or inhabitants from afar in space. But, it tends to be with aim at social commentary and character development, which many times those genres have the same aim. That said an Alien character development is kinda' limited to personifying human characteristics within that character. The social commentary perspective tends to draw comparisons with the human setting of the literature / film with historical context.