Immigration is not the same for everyone, as a matter of fact you can have two identical sisters submit the identical information (other than name of course) and you can have two different outcomes at two different times.  As such you should always strive to make sure that all of the information that you provide to the government if as accurate as possible and that you submit the supporting documents in your file, BUT, you should never compare yourself and your case to that of anyone else whom you may know or may have read about.  Remember, your file will eventually be reviewed by an actual person, not some computer, and as such each person will process your case according to his or her own time frame.