Why do people write viruses and other destructive software?

Certain people get a thrill from using their intimate technical knowledge of software, computers, and human behavior, to write destructive software which wreaks havoc in the workplace. Another chief reason that viruses are written is to seek revenge against Americans for being ahead in computer technology and in the business environment. Since it is now illegal to write software which destroys other software and data, the people who write viruses are not only doing it to get a thrill, they are also breaking the law and they risk severe criminal and civil penalties if they are caught.