Ever have someone beg you to read their writing? When you are a professional writer, it happens even more frequently, trust me.
Mostly, I would shy away from someone desperate for you to read their work. Sounds funny, but it's from experience. Those people for me, have tended to be amateurs. And I've read too many things like that already and it usually ends up wasting my time.
For most of them, if you try to help them, they really aren't that interested in getting better, in doing the work or in learning. They really just want to hear you say that it was great and then they would have written the great story, novel or script without any real effort. I first remind them that writing is rewriting, for any writer.
Anyone can write, but to turn out something good takes editing yourself. It takes practice. It takes learning rules and other unrelated to writing things. Most the time, people simply lose interest at that point.
I really have no time for people like that. After you've gone through that enough times, you get tired of even having to say no.
Now, on the other hand, if some friend can prove to me they are serious, then they can quite easily get my time. But I don't want to spend the time, to waste my time, when in the end, they don't also want to spend the time, especially if they simply want me to edit it, to turn it into some masterpiece for them. I have my own works I spent decades learning how to write.
I've run into this many times:
"Hey, I have a great story idea for a book, a screenplay, whatever. You should write it."
Usually they are passionate about it, energetic; they mean well. They just don't see it from the other side.
Problem is, I have plenty of my own ideas to write and already not enough time to write them. I seldom need other ideas. still, I will usually listen and be polite if I have the time. A friend just the other day had a great idea. I offered to him that if he would just write it up I'd work on it with him, but he really wasn't interested.
So I could only say that when I find the time we can work on it together. If I do write the script for it, I'll give him story credit. But he has yet to give me that. Maybe I should give him "concept by" credit or something?
Writing a book or screenplay, takes an intense personal and emotional investment. It's much harder, for me, to take someone else's idea and turn it into something if I'm not invested deeply in it. You can do it, but honestly, if it's yours to the core, you can simply do it to a more deeply passionate level. And that's what makes it all worth it. Otherwise, I might as well go back to being a technical writer.
Just my two cents. :)