It is a good idea to know which publishers publish which stories. For example, there is no sense in sending a picture book text to a publisher who does not publish picture books.
I think I am too interested in my own ideas to copy anyone else's, but I find that other people's imagery, the flow of language in the outside world, games with words, and ideas about relationships are all most important to me.
It can certainly happen that characters in more sophisticated stories can "take over" as they develop and change the author's original ideas. Well, it certainly happens to me at times.
When you are reading, someone has done a lot of work on your behalf, someone has had ideas and has then written and corrected and improved them so that they can be shared.
Try not to become disappointed if someone doesn't like a story you've written. Stick up for your ideas, but listen to what other people say, too. They might have good advice.