If members of the majority group are well educated and generally considered well off, minorities that are less well educated and less well off will look up to the majority group. The majority group will tend to look down on the minority group.
There are several reasons why the majority will look down minorities. The majority group will come to believe that members of the minority group have particular characteristics that cause them to be less successful (e.g. laziness, stupidity, dirtiness, smell, religiosity or lack thereof, etc.). These reasons will often turn into negative stereotypes of the minorities. The majority group will then come to believe that the negative stereotypes are true. The majority group will often not have the chance to correct their perceptions, because they are the majority, and have less chances of encountering and having significant interactions with a member of the minority. Negative stereotypes can result in segregated neighbourhoods and schools, further lessening the chance of perception-changing encounters. Isolation by race is probably the cause of extreme nationalist and supremacist groups.
Learning about other cultures is difficult and very hard work, that's why very few engage in it. It's challenging because it requires an open mind, a mind that is willing to see things by others' standards, and the ability to put oneself into another's perspective. In addition, there are little incentives for the majority group to understand the culture of the minorities, because minorities are 'invisible' and learning about them will have little material benefit. At times, the majority will expect the minorities to adopt the majority's culture, believing that the majority's culture is either superior, 'proper' (by 'national' or 'religious' standards), or both.
In conclusion, minorities often lead a life that is less smooth than that of the majority group. Differences in culture and numbers may lead to conflict and differing expectations, including that of 'racial roles'. The lack of reciprocal understanding of each other's cultures and problems is almost certainly to blame for these problems, but there is little incentive for the majority group to understand the other, leading to the less than ideal situation in which minorities are not well understood.