I found one in Jane Kenyon's Happiness, which begins:
There’s just no accounting for happiness,
or the way it turns up like a prodigal
who comes back to the dust at your feet
having squandered a fortune far away.
and continues with this wry image:
No, happiness is the uncle you never
knew about, who flies a single-engine plane
onto the grassy landing strip, hitchhikes
into town, and inquires at every door
until he finds you asleep midafternoon
as you so often are during the unmerciful
hours of your despair.
Go read the whole poem. I think she's beautifully accurate in saying that we do forgive happiness for its absence, the very minute it shows up again.
Elaine at Wild Rose Reader is hosting the Poetry Friday roundup today.