DD works in a hospital, she says sadly many older people become bitter and nasty in old age, for no obvious reason.
Maybe because they no longer feel the need or pressure to keep up appearances and pretend they're happy when they're not?
Maybe they're finally giving voice to that 'inner voice' that says 'what the fuck are you doing?' and 'will you just shut the fuck up!'* quite frequently, instead of supressing it for the sake of propriety, smooth relationships and other people's feelings?
*(Well mine does and I slightly dread the nasty horror that I may turn into with age, increased frustration and diminished impulse control. Menopause is bringing me close to spitting curses and obscenities inappropriately, daily, already! And, isn't this cathartic, sweary behaviour exactly what all those 'mummy drinks wine' blogs are about? What do you do when your fingers are no longer able to contain the sweary blogging for you?).
Maybe when your main companions, day to day, are people you don't love, care about, or want to develop long term relationships with and some of them are medical and care home staff who do painful things to you and often do take an unacceptably long time to attend to your needs, you feel quite justified in letting out how you actually feel about the situation?
None of that is the slightest bit difficult to think of, or imagine feeling. Where is the natural empathy and common sense of anyone who cannot easily imagine that?