Who says immortal people would behave like we see old people today ? With many of the biological clock and "not catching the train" stresses removed I would ima

Who says immortal people would behave like we see old people today ? With many of the biological clock and "not catching the train" stresses removed I would imagine mental health and general happiness would improve. And if you are living for hundreds of years, things will change around you and you will have to adapt anyway.