This attitude explains why Ed Wood was such a poor writer and director, why his films are incoherent.  The small details are, at the least, as important as "the big picture".

A work of art is created by the meticulous selection and accumulation of small details.  A work of fiction must be created brush stroke by brush stroke, as it were.  The writer may have a vision of "the big picture", but nothing works, particularly a plot, if the small, vivid, authenticating details are not there. Small, concrete details are usually the difference between a story that works and a story that fails, between a good piece of fiction and a great piece of fiction.

For instance, in Ernest Hemingway's short story Hills Like White Elephants, there is no description of the characters.  How they look is not important.  How they feel is, and their feelings are powerfully evoked through their dialogue.  The setting is also important, and therefore it's described in some detail.  The couple are at a literal crossroads—a railroad station—and a figurative one.  They must decide whether to have an abortion or dramatically change their life style.  The contrasting landscapes on either side of the station, one barren and the other lush, symbolize the choices they have.  In addition, the hills that look like white elephants are responded to with emotion by the woman and indifference by the man because the hills represent the pregnancy.  Knowing what the characters look like would not add to the story.  Their physical appearances are just not important, not part of the issues they are struggling with or the emotions they are feeling.

So you want to avoid details that don't contribute to the reader's intellectual and emotional pleasures, but more often than not, fictions are weak not because of gratuitous details but because of the lack of effective, sensuous details.  Your reader should see, hear, feel, taste, and even smell the fictional world you're creating.  And you can stimulate your reader's senses only with concrete, sensuous details.

Take risks.  Avoid flat, merely authenticating details that the story may be better off without, but don't be afraid of details with some emotional charge.  I often find that writers, out of their fear of being sentimental, will destroy an early draft of a story by stripping it of the details that gave it vitality.  If you are moved by a detail as you write a story, there's a chance the reader may be also moved.  If you're afraid of being called sentimental or of revealing something about yourself, you're taking the risk of never being poignant and of committing the greatest sin: that of being dull.

"The big picture" might not be much of anything new.  Take, for instance, the first Rocky movie, the Academy Award winner for best picture in 1976.  There's much about the premise of Rocky that would strike a lot of people as trite: a down-and-out boxer named Rocky gets a chance at the title.  Nothing very original about that.  But what makes the movie work is that the characters come to life so that the audience knows them and is interested in them.  Little details like Rocky's pet turtles, the photographs on his walls, the hole in his tee-shirt, the phrases he uses habitually—all these small things play a big part in his character development.  (The same would be true, of course, if Rocky were a short story or novel.)

By the way, the sequels to Rocky don't work as well, because the focus isn't so much on the people and the small details as it is on training scenes and fight scenes and melodramatic arguments between the characters—the sensational rather than the human elements.     

The subject of a story is almost always people, whatever else the story might concern, and originality comes not from the subject so much as from the treatment of the subject.  You don't need to search for something strange to write about—like a bigamist professional wrestler (although the story might be fine).  You can write about something that sounds, when summarized, mundane—for instance, an old lady who lives alone in a cottage in the woods and does nothing except work with flowers in her yard and drink tea before going to bed at night. 

It all comes down to the small details.  In the hands of a good writer, that old lady, her cottage, her flowers, and the smell and taste of her tea, as well as the feel of the smooth, porcelain cup in her hand, becomes quite real for the reader and the story truly powerful and moving.