I think that's a cognitive illusion, but I understand that it can generate positive emotions who are not an illusion, by any means.

More a legacy kind of consideration, really - I do not imagine any meaningful part of myself other than genes (which frankly I was just borrowing) live on. But - If I have done my job right, the attitudes and morals that I have should be reflected in my children, and so I have an effect on the world in some small way that lingers, even if I am not around to see it. And yes - that's comforting, a bit. Still would rather not die, but hey.