A lot of people liked his personality the second time, I don't think it was natural. It was always sort of phony and the same things about burgers and being an old man, but he did learn as we do when we get older to be more social. He used it to get more money and fame, and it worked. George is a smart man in business. As for him being polite like on TV, I have had some friends say when they saw George in person he was not very nice.
I think he did it as a business move, and pulled it off perfectly. Who doesn't like a big, strong, happy teddy bear that is constantly smiling and laughing? As far as how genuine it is/was, I think it is an act. I don't think he is a bad person, but I have heard that when the media or anyone of the sort is not around, he tends to be pretty stuck up. This doesn't make him a bad person, but he's hardly the person he makes himself out to be. I can't base this from a first hand account though, I've only heard things off of the grape vine.
I met him once. He seemed pretty nice, but he definitely had an agenda at the time: to sell his grills. But, like you , I've heard and read stories about how George is not so nice and loveable in private. If those stories are indeed true, and George is more con man than anything, that's pretty sad. I mean, him being a Christian ordained minister and all, you would think that he would live more by Jesus' teachings and be humble towards people. But then again, Foreman's love of money and fame seems to automatically put him at odds with what I know of Christian theology.
Being a preacher and having a church is just as much a business as anything else. A tax-free business.