And leaves no remnant by –
‘Tis Anguish not a Feather hath
Or too much weight to fly –
Happiness dissolves itself; flies away fast, leaves no remnants. Anguish doesn't go away. It either has too much weight, or even when it is weightless, lacks feathers. The purpose of life is not happiness. The purpose of life is to sing. Singing is an attitude of celebration.
Read what Aristotle says about happiness here: