Unhappiness is a palate-cleanser
Why is it impossible to always be happy? "But pleasure is often fleeting, even from the most appealing experiences, giving rise to ennui and sparking the drive for something new and sensational. As a neuroscientist, I can't help wondering whether the transience of our satisfaction may not in fact be inescapable and instead may reveal an inevitable aspect of the way the brain works, the understanding of which might provide a clue to how to contend with it." Indira M. Raman looks in Nautilus at why the key to contentment lies in its contrast, unhappiness.
From Nautilus magazine