This is true in theory, but I don't exactly agree. Sometimes your silence can be "misquoted" as agreeing with what someone has said. There are times you need to make your position perfectly clear, so that your silence in not interpreted as agreement.
You might think being alone makes you lonely, but that*s not entirely true. Being surrounded by the wrong people is the loneliest place in the world. Before you diagnose yourself as an unhappy person, first be sure that you are not simply surrounded by negative people constantly trying to bring you down to their level.