Yeah. But on the other hand, if you watch someone slowly decline in health because they did absolutely nothing to take care of their body, and then die more ignobly and miserably than they had to, solely because of that, it's a hell of a motivator to do another set of push-ups even when you don't particularly want to.

Strongly disagree. I used to have this opinion until I got genuinely very fit. Exercise is fun when you’re actually fit, in my experience. I never got the “runners high” until I was able to really push myself to (relatively) high levels of performance. YMMV

I mean, he was a professional athlete, so that’s kind of the point he was making. As you progress in fitness, it sucks less which means your body has adapted and you can go faster/ harder/ longer.