Why does Siduri tell Gilgamesh to get married and have children, how is this “the shape of happiness” and “the way to foil the gods”?

Siduri tells Gilgamesh that he is rushing to nowhere.... the gods allotted man death, life is short, and the way to foil the gods is to enjoy the life we've been afforded.

‘Gilgamesh, where are you hurrying to? You will never find that life for which you are looking. When the gods created man they allotted to him death, but life they retained in their own keeping. As for you, Gilgamesh, fill your belly with good things; day and night, night and day, dance and be merry, feast and rejoice. Let your clothes be fresh, bathe yourself in water, cherish the little child that holds your hand, and make your wife happy in your embrace; for this too is the lot of man.'