I'm glad for it too!

2011 - Developed condromalacia in both knees, which made pedaling, climbing and descending stairs painful.
A few weeks of PT appointments later, I was prescribed three 45 minute sessions per week of "homework". Those exercises built up the leg and hip muscles to support the patella as intended. Within a few months, the pain was gone, never to return. As a bonus I felt much stronger on the bike.
2013 - An old C7 fracture was rearing it's ugly head causing shoulder pain and arm numbness.
Once again lengthy exercises were prescribed, and once again the problem vanished in a few months.

I still do some of the exercises from both issue for maintenance as needed.

Discipline to keep up with the prescribed exercises was not a problem for me due to having pain as a motivator.