Yesterday, I did something I have never had to do in my writing career, and that was pull a submission. One that was already judged and a top-placing winner of a Christmas writing contest, with contract issued.
After careful consideration, I had to humbly turn down the contract offer and winning prize money. In regards to publishing contracts, I would urge every author to always read your publishing contract thoroughly. If you have any questions, never hesitate to contact the publishing company with any questions you might have about their contract offer. If they are not willing to work with you, then the likelihood is that they might not be the right fit for you and your work.
Another issue I would like to point out, if the publishers are not in the USA then you might want to think twice before contracting with them. The laws differ from country to country and some contracts would be null and void, tying up your work for years to come in litigations. I am not saying to never deal with publishers outside of the good old USA, but be cautious and well informed.