A publishing company needs to have a working calendar where we schedule due dates, press dates, release dates, etc. When I start a calendar year, I usually have a pretty good idea of which projects I'm going to be publishing during that year. I calendar their release dates according to a specific list of criteria. Due to budget restraints and other limited resources, I have to stay as close to my calendar schedule as is humanly possible.
Point One: The nature of the publishing business is that things are always getting delayed. It always takes longer to do something then you think it will. A key employee gets a two-week flu. The graphic designer goes on vacation. The printer has a brain cramp and forgets he agreed to do a project by a certain date. Shipments get held up in customs. Whatever. The bigger the publishing company, the more flexibility they have and the less likely the printer is to forget them, but still. It's always something. We try to pad our schedule for emergencies like these but sometimes things happen outside of our control. Yelling at US doesn't heal our employees or influence the customs master. We expect you, the author, to understand and be patient. We will be nice to you by explaining these things as soon as we know about them and we expect you to be nice back.
Point Two: When an author and I agree to a release schedule, and I tell them I need their finished manuscript by February so that we can release it at Bookseller's in August--and they agree--then I pretty much need their manuscript when I say I do. If the author doesn't get me their manuscript until April, then their project is now competing with another author's project and release date.
What am I supposed to do? Tell Author B, who did get their manuscript to me on time, that their book will now miss Bookseller's because Author A was two months late with their's?
I understand that things happen. Authors have real lives too. If life smacks you in the face and you're going to miss your deadline, let me know as soon as possible. Talk to me. I will be understanding. I will be nice. I might be able to swap your schedule with someone else's and get you both out in time for Booksellers. I'll certainly work with you as much as I reasonably can because I like your book; I want your book.
BUT I'm not going to bump someone else's book--which I also like and want--to accommodate yours. I'm not going to work 18 hour days and rush both projects through. I'm also not paying my employees overtime to get your book done so it can be released on its original schedule. I've already paid them for twiddling their thumbs for two months because your book wasn't there to work on when it was originally scheduled.
When this happens (and it does more often than not), please don't climb up my back or yell at my employees because your book wasn't at Booksellers as I'd originally "promised" and don't accuse me of breaking agreements and acting without integrity when YOU were the one who dropped the ball.
I will be nice to you, but I expect you to be nice back.