"Correlation always suggests causality, because where causality occurs, there is correlation; and a strong correlation is almost impossible to get due to chance. While it doesn't prove causality, until someone provides a different, plausible explanation for the correlation, the logical assumption is that there is causality here."

The beauty here is that it tolerably often gets the other person to look into the research, and more than one person has said after doing that and seeing how flimsy the research is in various topics, more than one person has eventually changed their mind.