Why do some people on here answer Hypothectical Questions with explainations on how they can never happen?

I mean, I understand the "how can I be a mermaid" and "how can i meet edward cullen and marry him" etc ones. The hypothectical ones are generally either curiousity or just for fun, and generally the people who ask them do know they won't happen, so, those of you who do it, can you answer me why you do it? Thanks =]