What is the one symptom or complication that is most troubling?

For me, the worst problem was falling asleep at the drop of a hat. It was horrible. I fell asleep at work, and during meetings. I finally got my cpap machine eight years ago. And what a difference!! Then the machine I had was recalled and I was without it for 1-1/2 years. It was horrible!!! Falling asleep any time I sat down. I finally fell off a chair because I was sound asleep. My shoulder still isn't the same and this was 3 years ago. Getting my new machine, finally, made a true believer of me. I hate the mask. It leaks often. Sometimes the magnet that holds the strap down pops and the machine starts squealing. And with all that, I am so grateful to have this machine. Because I know what it was like to have it then to have to give it up for awhile. It is literally saving my life.