Why do we get hormones?

Nature. Thousands of years ago, the desire for sex was for survival of the species. That has never left our genetic nature. And yes, some people have it "worse" than others. For some, it's almost completely overwhelming and overrides the brain's higher reasoning. Resisting the urge to give in to lustful passion is often a life-long battle. It is, perhaps, the reason for so many sexual activities that are lewd and lascivious. Nature made us this way and we try to resist it. Nature always wins - eventually.