From the most basic, practical perspective, which must also be a functional perspective, crime removes a degree of confidence in personal safety and the safety of certain material investments.
The presence of crime can lead to fewer social interactions and adjustments in commercial and consumer decisions when people feel that safety must enter into the decision making process.
According to the Social Interaction perspective, people tend to act and react to specific things based upon the meaning they attach to it. That said, conflict may arise of another person does not attach the same meaning to something and belittles the person, place or thing. Basically, this is the conflict which arises when the ideologies of two people or groups differ enough to make one side feel insulted.
From the conflict perspective, crime is caused by the conflict between classes and groups of people. Crime happens, then, because the rich oppress the poor. Or it happens because whites oppress blacks. This leads the oppressed group to fight back in various ways, one of which can be crime.