I am a rational person, and as such, have a biological view of life. I will still live my time, and at the moment of my death, I will be gone.
I therefore have to decide what to do with my life, based on the assumption that I will soon be dead.
With this perspective, I cannot see much meaning in anything else but the moments of optimal sexual satisfaction.
However, viewed rationally, the Western rational world is not the best possible environment in which a rational man can find optimal sexual satisfaction. This is the case because in a rational environment, I, as a rational man, will not have as much of a competitive edge as I will enjoy in an irrational world.
For optimal sexual satisfaction, love need be involved… already something irrational.
In a rational, and rich, society as the standard Western European one, the value of a partner in a sexual relationship heavily depends on his age. And yes, this discrimination, so-calledageism, is very much based on rationalism.