Mr Light wrote:
I'm still waiting for the cancer to come back. I think it being in remission for over a season was a mistake as it robs his original motivation from him. ...
That was the whole point though - he hasn't had his original excuse for ages, but he still does it. Part of the genius of the show is that there is no gimmick or mechanism which allows us access to Walts feelings, so his real motivation remains a mystery. What is he really
doing all this for?