We all know stories you write in the heat of the moment, but then when the muse is gone you give up.
My story Idea is this:
A man commits suicide and comes back to life as a mindless, gluttonous monster. He then attacks children which raises alarm and the police look for the missing children, only to disappear themseleves. A few years later a hiker goes missing in the same area, except of vanishing forever however his torn up body is found in a ditch.The townspeople look around the place the hiker was found and they discover the monster's lair. The monster has left long before they found it, but towns people find the children alive, but seriously messed up because the monster has been raping and feeding them human flesh.
Of course, you should go through with it. Whatever the finished product may be, it's always worth your time. I keep a file of all sorts of ideas, summaries, unfinished stories, scenarios, characters, etc. It's as close as I've ever gotten to writing a journal. Some of those ideas will eventually become stories, but most probably will never become anything. That's okay.
I keep plugging away until I have something to show for all my effort. I do it for the sake of expression. I do it for the writing practice. I do it for the challenge and a myriad of other reasons.
Consider your characters' motivations. Make sure their actions make sense and fit within the reality they live in. Most importantly, have fun. If you do end up with a story, then post it in the Writer's Workshop, so people can give you some feedback.