Ha, well, I do often wish immortality were possible. It would make sense, though I am not sure if that is it.
I think a big part of it is that there is too much I want to do, not enough time, and too much of the time I do have is "wasted" doing things I consider valueless but seem unable to avoid.
I am certainly very aware of my own mortality, and very prone to rumination.
I know what you have to say about that, and it isn't entirely wrong.