Everybody knows about the dybbuk and the Chofetz Chain. Rav Elchonon Wasserman used to tell the story at the Purim Seudah, But he said only those who believe in these things should be invited.
In other words these stories are meant as spiritual chizuk not as a means of convincing anyone about spirituality. In Making of a Godol (page 363-354) he also notes that his father was against telling spooky tales even about the Golem as it convinces some that Judaism is full of bizarre superstitions The above probably is true of Agada medrash and chassidic miracle stories