Dreams that happen without any influence of the activities of daytime have great significance and meaning. Such dreams should not be ignored. Dreaming of a dead person talking to you is a positive dream and it also many times warns a person about impending danger.
It is usually dead close relatives, parents, friends or family members that come in the dream. They are often well wishers and they might be asking you to be careful about something that is happening in your life. They also come to warn you against dangers.
But sometimes we see people who are not related to us. They might have never been our friends. Such dead people coming dream is often a sign of something bad going to happen. They are not to warn us but to confuse us and create negativity.
Always note that the dream should happen naturally and it should not be extension of what has happened on the day.