Emotions are what control what we do and how we act/react, pretty simple
It takes a lot to overcome your emotions if you are going to try.
From my experience when it comes to wanting to do it I had to be in the right emotional state to start my current weightloss endeavour. My mother first took me to Jenny Craig when I was nine years old and I have been on and off diets since then (I'm 24 now). Even through constant disapproving looks from my closest family it wasn't until I decided that enough was enough and I was going to do it myself. Knowing that I made the choice to do all this and make a lifestyle change was/is what gives me the self discipline to actually get through the tough times and the confectionery isle lol
I'm not saying that it can't be done using other methods but the way I see it is along the lines of you may get to your goal weight but without making a commitment to yourself to change what you're doing, it wont last in long run.