My main motivation is my health. My dad has exercised and eaten heathy since he was in his twenties. He's now in his fifties and doesn't have any health problems. My mom never took care of herself and now she's in her fifties and takes ten or more pills a day, doesn't have any energy, high blood pressure and cholesterol, overweight, etc. I've seen what can happen if you don't take care of yourself and what can happen if you do. So I exercise and eat healthy so when I get old, I'll still have energy and strength.
But to answer your question, no, not really. This particular case doesn't motivate me personally. When I see unusually obese people, I don't automatically think, "I must get on the treadmill now!" I guess it's because I can't fathom ever being that large. I have high metabolism, so I don't gain weight easily and maybe that's a reason why too. Anyway, I just fear living my last years in terrible health and that gets my butt off the couch and in the gym.
You cannot make yourself feel something you do not feel, but you can make yourself do right in spite of your feelings. - Pearl S. Buck