Studies suggest that aging brings a more settled and calm view of what one is, and what one is not, and a general increase in contentment. They also point to the sobering point that attentional and executive functions of one's brain apparently move (retreat) to more frontal brain structures, perhaps reflecting the increased effort and focus being required to hold things together, leaving behind fading richer and younger limbic and lower brain autopilots that once were more open to, and could juggle with, many novel contexts and feelings.
Just to keep current my list of the general litany of degenerative changes that can be observed on aging (present company excepted, of course), I thought I would point to this article from this past Sunday's NYTimes. Kate Zernike writes about turning 70, a recent transition for Ringo Starr who gave himself a 70th birthday concert at Radio City Music Hall (it happens to me in two years). I was most fascinated (and sobered) by what entering the +70 club gets you. I've rearranged part of their graphic to summarize some of the numbers: