It's a strange thought really. Deep down we need to admit that there is little "new ideas" resources this late in society, we document so much. Almost all ideas were formed from old ideas. Are they copyright infringement? Make up a new TV show, or invent a new story for a book, and chances are there already is a show or a book that is really similar. One that you may have read or seen and forgotten about, until it's pointed out that your story is the same as the one you read.