An argument that I often encounter when batteling pseudoscientific ideas is "So what? What harm does it do to anyone?" Alot of people seem to think that passing off pseudoscience as "fact" is a "victimless crime". Going to see the phychic doesnt hurt anyone even if it is bunk, people think. I vehemently think that this is not the case; psuedoscience, religion, alternative therapies/medicines and just plain nonrational thinking does countless amounts of damage and the loss of many lives every year. And I've found a website that will help get this across to anyone who still thinks that there is "no harm" in quackery.
Appropriately titled What's The Harm, this site lists case studies that are submitted by users about people who have been hurt, either physically, mentally, or finacially, by quack medical claims, religious beliefs, or other forms of pseudoscience and nonthinking. At press time, the site boasts a statistic of "2,435 people killed, 117,727 injured and over $115,817,617 in economic damages" due to such causes. Many of the people featured on the cite are innocent children, who have died because of their parents' religious beliefs, or because their parents chose "alternative therapies" as cures for their childrens' illnesses.
This is the reality of this kind of dangerous thinking, folks. Religion and peudoscience kills.