The title says it all.

Happiness Makes Up in Height for What It Lacks in Length
by Robert Frost

Oh, stormy stormy world,
The days you were not swirled
Around with mist and cloud,
Or wrapped as in a shroud,
And the sun's brilliant ball
Was not in part or all
Obscured from mortal view—
Were days so very few
I can but wonder whence
I get the lasting sense
Of so much warmth and light.
If my mistrust is right
It may be altogether
From one day's perfect weather,
When starting clear at dawn,
The day swept clearly on
To finish clear at eve.
I verily believe
My fair impression may
Be all from that one day
No shadow crossed but ours
As through its blazing flowers
We went from house to wood
For change of solitude.