Anti-social behaviour is not something that exists as an offence in its own right. It is defined as behaviour which causes or is likely to cause harassment alarm and or distress to others.
It is about a continuous, longstanding process whereby victims are repeatedly subjected to abusive behaviour from individuals who typically are known to them. It includes behaviour such as noise nuisance and other environmental crime, and verbal abuse and intimidation.
The court imposes an ASBO when it believes that the behaviour will not otherwise cease. Crime is doing something forbidden by law. That could mean theft, assault, fraud, selling drugs. Typically, it is a one off event in which victims and witnesses do not know the perpetrator. Crime is a serious matter because society finds even one incident to be worthy of punishment.
Anti-social behaviour is serious, even when individual events may not be noteworthy in isolation, because of the devastating effect that the process, the repetition and the context can have on victims, witnesses and communities.