Our dominant way of living is not sustainable and our activities as private individuals and households directly and indirectly account for a large and increasing share of total environmental impacts. These impacts are related to the structure as well as the level of consumption. In this article, research on the root causes of environmentally harmful human behavior is reviewed. Why is there no satiation of consumption in sight, even in the most affluent countries, and why do people continue to make choices that are known to be environmentally harmful? While potentially catastrophic, the harms from unsustainable consumption are mostly unintentional, which means that informational and educational means are not sufficient to produce the needed changes. They need to be implemented in concert with pervasive structural changes to make the right choice the easy choice.