“China” would have been my first answer to that question.
After spending so much time in a project that deals with massive amounts of HTTP requests from China, I realized that the majority of web developers are making too many assumptions. Several times I have found myself patching pieces of code because the connection was suddenly dropping in the middle of the operation, so I had to add retries and read incomplete streams of bytes to recover at least pieces of the actual data from our Chinese netizens.
In retrospective, I have learned a lot about TCP in the last year with this project.