Everything in human life/existence in general, comes down to sex, meaning the sexual impulse. Literally everything. Having sex is by far the most important thing you will ever do with your life. Sex is nature's (vastly) preferred mode of expression. There is no better use of time than to be having sex with someone. Forget having children, the very concept of reproduction does not have to be a factor. Sex can take a variety of different forms.
"Imagination, life is your creation"