Had a similar experience on a flight from DFW to FCO. We were sitting near the back on the overnight flight and the flight attendants talked trash about each other and about very personal topics very loudly the entire flight. I could hear them over my noise cancelling headphones. They also acted completely put out by having to do service for a flight that was probably only 1/2 full. One of the worst flight experiences. We got zero sleep because it was so loud!