Have you been writing your first novel, or even considered delivering on your dreams to write a screenplay? Shutting the door on your story means your goal will be to deliver a completed story without having it sit around for years in a stockpile of unfinished projects. Plan your stories as you would do with building something, anything really, that captures your imagination.
The most interesting aspect of writing is that you can write anything you want; there's no limits to writing. Writing only takes for you to decide on shutting the door on your story. Your stories serve no purpose when their collecting cyberdust on your computer, or when you don't recognize them anymore because it's been several years since your last writing binge.
Sometimes writing seem like an AA meeting to those that fear that they will actually enjoy writing a story. People would rather forget about their past projects, not wanting to take another dive into a story because it will attack their mind.
In no way is writing an evil ploy to starve your mind. Writing complimented with reading are a perfect team. You can stimilate your mind so fast it will actually surprise you. Shut the door on your story now because you can then begin another project.
You don't have to be a serious writer to write. You can dedicate yourself to write for a few moments in a day. It really doesn't matter what you write, only that you take the next step into working on shutting the door to your story and moving onto another exciting story.
Deliver your success today, don't wait to reflect on should've, could've, would've. Do it now! Write your screenplay, novel or school project. The longer you wait, the harder it will be later on. There are no rules to writing, only the ones you make in your stories. Shut the door on your story, realize your potential as a writer.