So i know I'm a little late to the game on your post, but better late than never, eh?
I'm still pre-op (hopefully this month!) so I can't answer questions RE: complications. I can say, however, just as with anything, you get out what you put in. Listen to what your doctor has to tell you, and take it to heart. I work in the medical field and I know how time and time again, people disregard the doctor's direction and that's when complications arise. Now, everyone is different, but you can mitigate the complications with being proactive in doing what the doctor tells you. (again, late in the game, so hopefully you've already had sx and are doing great without complications!)
As far as justification, though....this is what I say. The only person you have to justify it to is yourself. Seriously. Sure, I looked for approval from my (very skinny) best friend before I seriously considered anything. Then I sheepishly told my mother. I, too, have told very few people about my decision for WLS. I guess I'm afraid some people will consider it a cop out. I've talked about it with my parents, brother and his fiance, and a few other people like my doctor and close coworkers. You know what I've found? The few people who's opinions REALLY matter (aside from my own) are the people who have seen me struggle with my weight, every failed diet, every moment of depression and anguish, and yet, they've stood by me. I know that those people will continue to do the same because they know as well as I do, for me...WLS is not a cop out. It is going to save my life. If they really care about you, what more justification do they need? None.
And to those who aren't understanding. Educate them. Clearly they need it.