There are certain harmful behaviors people are tricked into engaging in, because whereas the benefits of the behavior are concentrated, the harms are diffuse or insidious. Therefore, when you benefit, P(benefit is due to this behavior) ≈ 1, but when you're harmed, P(harm is due to this behavior) << 1, or in the insidious form, P(you consciously notice the harm) << 1.
An example is when I install handy little add-ons and programs that, in aggregate, cause my computer to slow down significantly. Every time I use one of these programs, I consciously appreciate how useful it is. But when it slows down my computer, I can't easily pinpoint it as the culprit, since there are so... (read more)