Emotions and personal biases have a profound effect on how you think about something and how you eventually act. Let me give you a few example.
If a person is a racist and does not like a certain group of people, then he or she will have prejudices against that group in his or her decisions. If this person happens to be a a college admissions officer (as an example), he or she may not admit that group into the school. There will be other ramifications as well. His or her family perhaps would be influenced as well - the children may take on similar biases.
A recent example can be seen in the IRS scandal. Some people in the IRS targeted organizations that were conservative in political outlook, and consequently gave them a harder time.
In short, biases and emotions are powerful motivators.