You'll feel the need and unhesitatingly, you'll feed it and fill it with all you've got.
And then comes the reward. Oh, the reward! The unparalleled satisfaction, the immense joy, the unparalleled high. An unexpected kiss, a bear hug, a silly smile, a grateful look in the eye ... any tiny gesture of appreciation and everything is worth it. Everything. One good day out of a hundred embeds in the memory and keeps hope and happiness afloat.