Fantastic responses! Its wonderful to get so many perspectives on this one. For the sake of the thread, I'll take issue with the "just cheer up" line of thinking. Depression is not a choice. In much the same way you don't tell an alcoholic to "just sober up", or tell a homeless person to "just buy a house", or tell a cancer patient to "just be healthy", you cannot tell a depressed person to "just cheer up". Too many of the features of depression are not under our direct control.
To be sure, we have choices about our attitude and we can hold our heads up even when our necks hurt. Smiling costs so little. Be strong, be positive, get involved, be in the now, live every day, etc., to be sure. Though great advice, these are NOT at issue here.
To me, this is not a "rah, rah, sis boom bah", pep-rally issue at all. Its more unconscious, it arrives in my world unsolicited, unbidden, unexpected. It pops up even when I'm having a great time - hope/doubt. It is now clear to me that these two travel together. Hoping for a thing is an admission that it might not occur. This is not some huge cartoon ship's-anchor that I am forced to drag about with me, its more like a bird that occasionally crosses my view.
Mortality is sobering at its least. It makes me aware that I have lived 50+ years without any concern at all about how many chances I will get to do a thing. This is no longer true. When my barber shaved off the rest of my falling hair during chemo, he asked what my odds were. I told him, he frowned and said "well, is there any place you really want to go?" Utterly practical. His comment may the genesis of this discussion for me. I am now forced to make better choices with my time - no matter how much of it I have.
Does any of that make any sense? Tom