I have this conversation a lot with some people I know who are always "looking to lose" or "planning to start dieting next week" or "trying but I get so hungry." I know that there are genetic factors that influence my metabolism and my hormonal state. I know that people in my family tend to gain easily, and that we are all apples. Some people in my family rest on that knowledge, and don't accept ANY of the blame for their health problems. However, I feel that despite any other innate factors of my metabolism, my weight is my fault.
I spent years knowing that I needed to eat fewer calories and exercise more, and not doing it. Those two things have been totally within my control and I didn't do them, so none of the other contributing factors really matter. The bottom line was that I wasn't doing my part to mitigate those factors.
It certainly sucks that I am short, and I don't have a great metabolism. It sucks that for me to maintain a healthy weight will require a low intake, about equal to what taller people reduce their intake to when they're trying to lose. It sucks that I have to work so hard to make any progress. But it's not an excuse, and it's time to suck it up.
Mini goals keep me sane...But I never forget the bigger picture!