The group delusion

Political, economic or religious groups don't exist in the real world. They're a product of our minds.
Of course, even though these groups are not physically real, they are treated as such, leading people to identify as members of one or more of them. These individuals do exist—they are real—and as they declare their affiliation with a group, we also assume the reality of the group itself.
That's where the delusion starts, but it doesn't end there. We profile groups, therefore we have a pretty clear idea of a set of characteristics associated with each one of them. As a consequence, we tend to attribute that set of characteristics to all the group members, as if they were not unique human beings but just repetitions of a certain pattern. A procedure that would appear unacceptable if it were applied to us, is light-heartedly used to simplify the rest of the world.
This might be fine under certain circumstances. However, we need to keep in mind that hardly any of those group members will be correctly described by that specific set of features. In fact, the majority of them might not showcase most of those attributes at all.
This distinction is not just important; it is fundamental. The consequences of this mental trap can lead to social disaster.
Groups can be very useful as conceptual tools. Be extra careful not to take them too seriously though.