As an author, you expect readers to respect your intellectual property rights. You have a similar obligation to the authors of any works you cite in your manuscript. By limiting your quotations to what’s considered “fair use,” acknowledging your sources, and securing in advance any needed written permission, you prevent the risk of delays in publication or legal penalties.
Likewise you save yourself grief by taking pains not to commit libel—or to offend your potential readers.
Presenting your material in the expected, professional format makes your editor’s job easier. By formatting your manuscript correctly, you enable your editor to concentrate on your words.