Mending a Wall

Mending a Wall is a very thought out poem. It takes you to a farm where every winter this wall that divides Robert and his neighbor falls apart a little. And every spring Robert and his neighbor fix it but never speak more than that.
"But at spring mending-time we find them there.
I let my neighbour know beyond the hill;
And on a day we meet to walk the line
And set the wall between us once again.
We keep the wall between us as we go."
So eventually Robert asks why they built this wall? He has apple trees that would never grow onto his neighbors pines. When Robert asks his neighbor his neighbor replies " Good fences make good neighbours.” When you look at that quote from the neighbor it doesn't really make sense because if they had a good fence then they would never talk and never see each other.