In uncertain situations, we often look for social cues about what to do based on what everyone else is doing. This kind of "social proof" can be highly effective in helping us to navigate what to do in the absence of proper information. In fact, sometimes the effects of social proof can be remarkably powerful, causing the herd to do something dramatic "because everyone else is doing it too," even if no one in the crowd actually knows why they're doing it!
Unfortunately, though, the principles of social proof are often used unintentionally, and in fact can be unwittingly applied to encourage negative behavior. From teenagers making irresponsible decisions because their friends are doing it, to baby boomers not saving for retirement due in part to a perception that no one else is doing it either, it's important to consider the social proof ramifications of any message that is communicated. Otherwise, there's a risk that explaining the commonality of a bad behavior will actually communicate to people that the behavior is socially condoned and that it's ok to do it!
On the plus side, though, financial planners are often in a good position to invoke the positive effects of social proof on behalf of their clients. If the "normal" behavior is bad, we can establish positive role models of what the normal behavior of a "good" outcome would be instead. On the other hand, applying social proof with clients also requires us to let go of the idea that absolutely every client scenario is completely unique, and instead try to identify ways that a client's situation are similar to others, to provide a positive social proof context. But the bottom line is that since our brains are hard-wired to create these kinds of comparisons, just ignoring the phenomenon is not an option!