The meaning “good fences make good neighbors” originated from Robert Frost’s notion in “Mending Walls.” The saying implies that with a fence between neighbors you can each maintain your privacy. When people become complacent about their neighbors privacy or wishes then ill feelings can occur. If your neighbor has the run of your yard there is always the chance that they might do something against your wishes. This does not imply that they are going to irritate you on purpose but there is the chance. A fence between the properties will eliminate the chance that they may trespass into something that you do not want to share. This is also not just about a physical fence. It also means that your neighbors should not have free run of the knowledge of your lives and what goes on in your household. There has to be boundaries in all relationships which would constitute a fence. In regard to the actual fence it should be low enough to allow communication between the neighbors while keeping some things out. The same applies to the personal fence. Do not build a stone wall between each other that allows for no communication.
I believe that any division between one another constructing a boundary may create a safe and secure feeling, but it also creates isolation between one another. In the long run it can create a dispute over the need of a wall, which will create an emotional wall; Here you have two people with different opinions about the wall, one who wonders and thinks about "why", and the other who is stuck in old tradition and doesn't question the necessity of the wall, probably not even understanding his own motives.