From Basic Judaism, by Rabbi Milton Steinberg:
From the presence in man of a divine element two implications flow:
He owes himself self-respect, a dignity of thought and action befitting one in whom burns a spark of God.
And he is under the duty to express his individuality. For bearing the divine image, he bears it uniquely. No one in all the world exactly duplicates him. Therefore he is obliged to discover and develop his uniqueness. Otherwise, to all eternity some aspect of the divine nature shall have been left latent and unfulfilled.
On why asceticism is not a Jewish ideal:
…he shall invest everything he does, no matter how menial or carnal, with Kedushah, or holiness; that is to say, with intimations of the divine and ideal.
It is right and good that he should eat with relish. But let his meal be more than the appeasing of hunger. Let it serve as an occasion for the strengthening of family ties, for the association of friends, for the exchange of “words of Torah and wisdom.” Let it be hallowed further with religious exercises. So a man may eat ever so zestfully and still be no beast. His table is an altar.
Sex, too, is sanctified…