We always seem to forget that others matter. The words that come out of our mouth indirectly affects others. The world doesn’t matter when you are conversing with another one on one, but the whole world is listening. Everyone knows.
People enter and leave lives all the time. Some leave a stronger impact than others. Bridges are rarely burned, but rather they crumble from a lack of maintenance. Once we stop caring, there is no longer a need to feel any sort of emotion for them.