I don't know horses. I've seen policewomen/men riding them two abreast down a city street, (Ha! Swallow that, impatient drivers!) though probably just to give them exercise.
But horses were common only a few generations ago.
(So what's the point? :confused: )
Ok. Here's the point:
People used to use horses, donkeys, oxen, camels, elephants, etc. (and still do) to provide power for their work and travel. They understood that you couldn't run a horse (or animal) forever, that that horse needed rest and food to recover. They are strong, but have limited power, since they are flesh and blood.
In a similar way, cyclists must have this awareness about themselves: we are flesh and blood, too. We need proper rest, food and recovery to go the distance. This is indeed an important thing to know about oneself.
Motorists don't have this basic awareness of themselves. I feel sorry for them!
(Comparing yourself to a horse, Pete? "Hello, I'm Mr. Pete!" A horse is a horse, of course, of course...)