Was somewhat randomly reading some diary entries from Jonathan Edwards, and found these observations about what old people can be like, and his resolutions for the future...
"Monday , Sept 23 [1723?]. I observe that old men seldom have any advantage of new discoveries, because they are beside the way of thinking to which they have been so long used. Resolved, if ever I live to years, that I will be impartial to hear the reasons of all pretended discoveries, and receive them if rational, how long soever I have been used to another way of thinking." (Memoirs Chapter IV)
"Saturday, Feb. 22 . I observe that there are some evil habits, which do increase and grow stronger, even in some good people, as they grow older; habits that much obscure the beauty of Christianity: some things which are according to their natural tempers, which in some measure prevail when they are young in Christ, and the evil disposition having an unobserved control, the habit at last grows very strong, and commonly regulates the practice until death. By this means, old Christians are very commonly, in some respects, more unreasonable than those who are young. I am afraid of contracting such habits, particularly of grudging to give, and to do, and of procrastinating." (Memoirs Chapter V)
(I think he was about 20 years old when he wrote these... not sure how old is "old"..!!)