Very usually out of the ordinary

Fabulous title, huh? Someday i'll write a story with that title, maybe even a book, who knows. In the meantime I'm preoccupied with finding titles for things i've already written. What is in a name, anyway? Is the title, A) a way to tidily package the meaning of the piece, B) a gimmick to interest the reader, C) strictly informative of content, or perhaps even D) something that came to the author in a dream and is completely unrelated to the piece at hand? How does an author or poet choose a title that isn't melodramatic and vague, and still tells the truth, without turning into a sentence long ordeal? Or is a title even necessary?