Why do people hate their grandparents?

This is just my opinion, and I have never hated old people, but if someone does hate old people I think it may be because an old person is a very vivid picture of who and what one becomes with loss of health, loss of status, loss of opportunities, loss of sexiness, loss of hair, loss of memory, loss of coordination, loss of bowel and bladder control....it could be what is in store for us young'uns. So the hate is fear-based. The fear of becoming old.