I don't have to modify anything in the Insanity workouts, despite my illness and I find it fun to clench my teeth and think that every-time I push through the burn or do a punch that I punch right into the face of Multiple Sclerosis and every second I can go longer and digg deeper is a defeat for the illness itself and a victory for me.
Besides the general wish of being healthy and look good, it's the most important thing that keeps me motivated and willing to push.
My Motto is, if you are confronted with a new negative situation you are left with two choices: Adopt to it and/or if you can, change it.
It doesn't matter why you ended up in this particular situation, if it was an outcome of your own decisions or if it just happened without you influencing anything. You are in a situation you don't like RIGHT NOW and you have to decide what to do.