Just a little thought: often when reading about scientific studies done, one will read things like (made-up example):
42% of people who spent less than half an hour weekly using a blender called themselves 'very happy', compared to 34% amongst those who spent more.
Thus implying or directly saying that less use of a blender is causing more happiness.
But I think in many cases or the majority, it's at least as likely that the two facts are accidental or they may be caused by the same thing, for example that blue-eyed people are less likely to use a blender and blue-eyed people just happen to be happier for some reason. Or heck, maybe they are using blenders less because they are happier, the opposite causality. Probably the perception of the causality is much more based on the expectations rather than the numbers.
Update: Ken said...
I teach statistics and one of the things that we try to convince students is that correlation doesn't imply causation. Sometimes it can be possible to have a reasonable conclusion but often not.