@Caroline,
Well what about if there is too much love going around that it loses its meaning or value? I think we cherish love because it is a rarity but if it were spread more commonly people might grow tired or indifferent to it. A new type of rebellion would happen.
Imagine everyone being nice and respectful to each other. There would come a moment when the opposite, a rude comment would stick out and people would be in awe of it. Eventually it would become the new norm since it is rare.