zero.  
It starts with nothing.
A spark in the heart, a glint in the eye
to begin increasing up the hill.
He asks, she says yes.  
The slope climbs rapidly up the y-axis.
Under the curve, values fill with knowledge of the other,
Care, and even a little love.
The critical point, a relative max
A quarrel here, a fight there.
More than two negatives exchanged
decreasing to a resolution.
Another critical point, a relative min
The slope is zero.
Both parties stare at each other.
Yet alas, two negatives create a positive
They bring each other close and begin to weep
and the function increases once again.
Sometimes lower, sometimes higher than before.  
Where the values are greatest, the absolute max.
The happiest point.
She smiles at him, green on brown.
Moments are shared that last forever,
but as the slope falls once again
more critical points are left behind.
This fight, bigger than the rest
the slope hurtles down the graph
without a resolution.
Down, down, down
until they reach zero once again.
“Enough is enough, it is over.”
And they take their final step
below the x-axis.
Where the values are least, the absolute min.
The saddest point.
Both parties miserable
with pain for themselves, and the other as well.
The interval is closed.
[b , e], from beginning to end.
A relationship is a function
with ups and downs, maxes and mins.
But, though the extrema have been found,
The function continues on.
From here on out,
the grapher plots the points.
Whether to teter into the darkness of the negative realm
Or to stay constant, pick themselves up
So they can increase back
to zero.