One of the main reasons I have not quit smoking again is that I have tried to quit so many times and have discovered myself snapping at friends or family over trivialities as I go through the withdrawal process. Each time an instance like this happens, after the passions cool, I feel confused as to why such a small thing would set me off. As a smoker, that never would have happened. The triviality would be bundled up and reserved for a smoke where it may not ever have to even be acknowledged. It's as if there is a little room in your brain and you can just put things in there and literally set them in fire and create them. A fairly useful little tool!
I guess what this essentially means is in some warped way, I've felt guilty trying to quit because of the unkind way my nicotine-less self treats those I care about around me. Nor am I yet fully equipped with another room with which I can put those stressors.
Having quit for a year once and then two months last year, I recognize that these flare-ups are temporary and not completely the "real me", however I also recognize that they are a part of "real me" because at the end of the day, I have the willpower to stop smoking - I've proven it. But so far, I've never had the willpower to never smoke again. So I guess by deeply choosing to never smoke again, I'm allowing myself, my body, my brain chemistry to become the fullest example of who I really am. I suspect that that's better than the me with nicotine.
My addiction wasn't going to damage my relationships any more so I kept my mouth shut for the first couple weeks of my quit. Instead, I did yoga, went for walks, keeping busy enough to burn off that negative energy. And when I did snap at someone, I apologized. 
