I have done a lot of thinking on this subject over the years. From what I have been able to figure, the reason we are hit so hard by certain celebrity deaths, say the late, great Robin Williams, is because, even though we may not know them personally and may never meet them, we allow them into our lives on a nearly daily basis. It is almost as if they are a part of our family. They become such a part of our lives that when they are suddenly taken away from us, we grieve as though we have lost an actual family member. Whether or not we have friends or family to lean on in rough times, we always have TV, music, movies, books, etc. They make us feel better and oftentimes we find certain celebrities' work moves us more than others and this brings them closer to our hearts, and when they are suddenly ripped away from us, and that realization that we will never see or hear from the ever again sets in, it hurts. It can hurt a lot.