friends that we were particularly close to and spent most of our time with, the ones with whom we shared the ups and downs and traumas of early adult life, whose advice we sought in those moments of deep crisis, the ones we sat up with late into the night discussing deep philosophical issues, the ones we most regularly went out drinking or partying

Old age brings on a downward spiral in which all the odds are stacked against you. You find it hard to make new friends as your old ones die or move away because you have less in common with the younger folk who now make up the bulk of the population;