Those are our Happiness questions today. But first I have to say: Happy Birthday, Older Daughter! The day of your birth back in the halcyon '90s was the least Sisyphean, the least routine or repetitive, the most inimitably joyous, I'd ever experienced.
Did Sisyphus have kids?
If all the days of your life, save one or two, were filled with unpleasant drudgery, but those one or two were as ecstatic as the birth of a child, would you call yourself happy? I think I would. Fortunately I've had many more than one or two great days, and relatively few days of dread. Thanks to my walking habit, even most of those were salvaged by a happy hour away from the rock of pointless routine. And because I find my teaching vocation mostly gratifying, most of my routine feels purposive, not pointless (except when pushing paper and filling out forms for our administrative overlords).
If Sisyphus had no children, no down-time to himself, and no hope for early retirement, I really can't imagine him happy. (Maybe he was a secret Buddhist, meditating on the transience of existence and willing the good of all sentient beings, behind his rock.) Nor can I really imagine Samuel Beckett's "Unnamable" happiness: "I can't go on, I'll go on." But apparently, happily, some can.