Some people do just "Stop", and I don't think anyone really knows why. People do not believe that I am 56. Twice this year, I have been asked to show my driver's license, because they
just don't believe it. "My father's your age, and he looks so old!" states one 20-something female co-worker. Another tells me that all her husband wants to do is sit and watch sports on TV.
He is 58, and headed toward diabetes, according to her. Apparently, he does not care.

So, why is this? No idea, but it does seem to me that some people do indeed "just give up".