i've had the same decision and the same answer :)
Well, you're right, sometimes its hard to talk about these sort of things. I tried to type it out first, but it was (and still is) pretty personal and difficult to talk about with people I don't trust completely, so I'll give the short answer, and that will have to do.
About two years ago, almost to the month, I was hospitalized for a week for a very serious heart problem. Basically my heart was beating completely at random (atrial fibrillation), at 180+ beats per minute (resting!), had swollen to about 2 or 3 times the normal size, was putting out about 40% (maybe less) capacity, and the pericardium (sac that contains the heart) was filled with fluid. After a battery of tests including blood, cultures, and a very "pleasant" spinal fluid tap, the ultimate cause of this by one of the top cardiologists in the state was "I dunno. Maybe a virus?"
I was 26.
What I will say is that it was a very difficult time full of a lot of stress and worry. The hardest decision was about 4 or 5 days into that whole scenario, after getting no sleep at all (I think I got maybe 8 hours of sleep over that entire weeklong period). I was panicked: I did not want to die.
But that wasn't the hardest decision I had to make. The hardest decision for me came just after.
WHY don't you want to die?
What happened after, I don't know. It was something very personal, something I often wonder about, and something I think on from time to time. I'm still trying to come to terms with everything that came after that, but THAT was the hardest decision I ever had to make.
Well, so far, anyway. The good news (spoilers) is that I made that decision. I think you can figure out what it was. :)