During the document collection phase, we did hit a glitch or three. Carolyn's birth certificate request came back because South Carolina had increased their fees for certification. Our adoption consultant handled if for us, but it caused a two week delay. Next, the INS made us amend our I-600. When we filled it out, we were undecided about what country we would adopt from (we were considering China, Vietnam and Thailand) so we arbitrarily put Vietnam on the form. When the INS got the home study (where we had decided on China), they required a letter to amend the document. Another two weeks. Then, when Carolyn traveled to our doctors office to get our medical forms, somehow, magically, or as Emma would say, "it did it all by itself". the forms got left on the roof of the car when it was driven off. Ouch! Fortunately, our doctor simply recompleted two new forms from his records and all was well (after several more days of delay).
All in all, not too bad and very little stress.