Just an opinion here,
With CF it is very tough. When I was young and in my twenties, I remember thinking to myself that if I do not do my therapies it is like slowly killing myself. I thought to myself, "I am not suicidal" When I got to that point when I was tired of fighting CF it was like an alarm that went off. I quickly became motivated as I knew I had no choice but to do the therapies all the time so I can live as long as I could and maximize my healthier years. I was always very compliant with the therapy. I do not think I missed a treatment ever in fact I always did more therapy but there were times where I wanted to skip a treatment and then the thought of what if came up.
IT is not easy living with CF and I can say I have been to the point of no return and was saved with a transplant. I can say that even when you get really ill always try and do the best you can with your cF because even when you are sick you will see that it will not be as bad. Giving up will take you on a downward spiral and it will be a slow climbing up hill. There is always hope.