This phenomenon occurs for a number of reasons, none of which may satisfy those that have been on the receiving end of such an experience. It seems people are so very scared of the break up conversation that they are willing to cause the unnecessary pain that follows a ghosting. Sometimes it is the fear of the reaction that will be received that can cause such behavior. Perhaps they had been through a difficult break up in the past and wish to avoid any and all difficult break ups in the future. Some people simply want to avoid being uncomfortable, and will cause others pain to avoid their own discomfort. A simple thanks but no thanks, or a I'm just not that into you may take courage to say, however it seems a vast majority of the dating population seems incapable of exhibiting this courage.
Showing respect to a relationship, or the people in that relationship is the defining characteristic to a healthy relationship whether it continues or ends. Taking the time to end that relationship in a definite and finite way exhibits true character. Taking the time to let someone down says a lot about who you are, as does letting them forever wonder what happened. You might ask yourself, what would you prefer if you were the person being broken up with? Showing compassion for others whether you want to be with them or not defines your character, as does complete avoidance. Do not let the ghosts of relationships past keep you up at night by working toward a respectful end for relationships with someone you may have have one time cared for.