One of my fellow aspiring writers--who I critique for--recently had some very unconstructive criticism. This writer fellow of mine is fairly new to the game and this is his novel numero uno, draft two, which he has sent out for us, his readers, to critique. One of his readers read three chapters and told him that the story had no merit and that he should move on. He at least said he should move on to a different story and not give up writing all together, but still! Unconstructive criticism!
First off: how can anyone tell from the first three chapters if a plot line has merit? This is why agents ask for summaries with partial requests. The first three chapters do give a person an excellent feel for the writer's style and whether their writing has merit. But in the first three chapters of Harry Potter and the Sorcerer's Stone did JK let us know about Professor Snape--one of the greatest character/plot lines ever? No. In the first three chapters of The Hunger Games did we know that Peeta like Katniss for realz? No. In the first three chapters of Ender's Game could we have guessed practically anything to do with the plot? NO! You can't judge a plot by three chapters.
Second off: Not every story is publishable, true. I myself have at least five completed novels lying around my apartment that I will never ever publish. I would be ashamed if they ever escaped my shelves. But each of those novels was a learning experience! I do not regret writing a single one of those stories. In my opinion, unless you--the writer--are no longer satisfied with the story line and no longer think its appealing or worthwhile, you should never stop writing it. Write it to completion. Revise it. Revise again. Even if its not publishable. Writing and revising will teach skills that you can't gain any other way. Skills you need to write that publishable book.
I've read about seven chapters into the manuscript that the other reader deemed "worthless". It's true that there is a lot of work that needs to be done. My comments filled the edges of the manuscript (though I tend to be verbose in general--even if the manuscript is awesome). But it's only a second draft. A lot of work always needs to be done at that point. The plot seems to be moving along quite well from what I can see. I point out things that don't work for me, things I think he should expound upon, opportunities that I feel he missed, etc., but I never say "this is stupid. Move on with life."
Because it isn't stupid. Writing never is. Everything we write as writers hones are skills. So even if what you're writing never will be published, it's still worthwhile. We are learning every time we write a paragraph, every time we revise a chapter.
Unconstructive criticism is worthless and should be viewed as such. Yes, it hurts when a reader completely disses a manuscript. But put it aside, move on from their criticism. See if you can see what they're saying, address it, but don't let it get you done.
Your writing is worthwhile.
Note: It should be pointed out that unconstructive criticism and harsh criticism are not the same thing. The difference is that a harsh criticism points out the faults but also gives suggestions on how to fix it (or at least starting points to go from or points to think about). Unconstructive criticism is when people say something like "This is stupid" or "give up."