So I was just thinking about this, as I do far too much, and was struck by something that I often say to people when they lose someone. If it hurts that means you had something worth losing. When my dad died it didn't hurt much. I probably mourned more for the dad I never had than the one I did.
So if I flip that around, I guess maybe if it hurts more to leave this planet it's because your life was worth something. If it didn't mean much and was one of resignation, then maybe it doesn't hurt as much to leave unless one has regrets. I have too much to do and experience to leave. I want my life to mean something now that I can see clearly, and it devastates me on a level to know that will end someday.