The very root of this word indicates that prejudice is something that confronts common sense, that is, prevents it from moving forward.
If a person breaks his arm, then, as a rule, he immediately consults a doctor. Friends and even unfamiliar people will sympathize with him and, perhaps, even help to cope with affairs that require a certain dexterity of both upper limbs. However, not all diseases cause such unambiguous sympathy.
In the Middle Ages, European countries were in a panic: the townsfolk from all sides were surrounded by witches. In order to get into their number, it was enough to have red hair, and sometimes just to be a beautiful woman. Checked by a sorceress simply: tied up and thrown into the nearest body of water. If the poor fellow emerged, it was "clear" that she was a witch, and therefore was to be burned alive ...
Why in some cases do people avoid communicating with those who differ from them in some rather abstract way? Especially if these personality traits are not related to possible upcoming joint business? Obviously, there is prejudice, that is, prejudice. This is an opinion imposed by someone or voluntarily accepted, transferred to a specific person.
There is such a thing as xenophobia, that is, rejection of everything that is characteristic of customs and mores, and sometimes the appearance of residents of other countries and continents. At the same time, many differences are fictitious, and with the light hand of some unkind or stupid person (and possibly groups of individuals) have become public opinion. Stereotypes and prejudices against foreigners occur in almost every country, and ascribe to owners of a skin of a different color or face of a different shape some rather nasty character traits or a tendency, for example, to a parasitic way of life. So, in the famous tale of Eugene Schwartz, the archivist is convinced that the gypsies are scary people. Moreover, he himself did not see any of them.
Campaigns in some republics of the former USSR during its collapse, when the idea of "insidious invaders", besides drunks, who are the time to clean up with the suitcase directly to the station, could be considered numerous examples.
In addition to racial or national, there are social prejudices. They mainly manifest themselves in relation to those who are at other levels of the social hierarchy. Most often, more successful fellow citizens experience contempt, and sometimes hatred, for the poor, or those whom they consider to be. However, it happens the other way around, when any successful person is obviously considered a villain and a thief. Sometimes such sentiments are fueled by politicians, based on some kind of personal interests.
And one more kind of bias. Religious prejudice is intolerance towards people who profess a different faith. It is these differences that often became the cause of wars, the collapse of prosperous states and genocide. The basis for propaganda of hatred has been centuries-old prejudices that someone did not need to take a lot of effort out of the subconscious.
Of course, not all intolerance is a vice. There are customs and mores that contradict the norms of a civilized society (for example, cannibalism). But for the most part, prejudice is a very unfortunate phenomenon that interferes with the mutual enrichment of cultures and mutual understanding between such different and always in their own way wonderful people.