Serene is an emotion few and far between :

calm, halcyon, speaceful, placid, tranquil,collected, composed, even-tempered, unperturbed, pacific, still, cool, sedate, self-possessed, drowse, doze, nod, snooze, nap, rest, slumber, fantasy, illusion, mirage, vision, aspiration, desire, goal, hope, wish, muse, reflect, rhapsodize, fancy, imagine, visualize.