I'm sorry this upset you. Being an older person myself I can relate to this topic. As with most things, I think it depends. I'm sure, working in a nursing home, your friend sees residents who have indeed lived longer than is useful in any meaningful sense (unless one considers sitting slumped over in a wheelchair all day to be useful.) On the other hand there are older folks (folks even older than me! ) who are still healthy, productive and able to lead personally satisfying lives. I think the key is to stay active and involved as you age in pursuing whatever interests you. (It also helps to have good genes!)