There are several options. Sometimes they overlap:
- Direct gain such as romantic opportunity from sabotaging a rival or items of value from theft. Some people are callous about the harm caused, while others rationalize it as necessary or justified.
- Retribution or justice. Most people are happy to hear that a child molester will receive abuse from other prisoners, to give an example.
- Sadism - direct satisfaction or pleasure from causing pain to others. This is unlikely to make much sense to those of us who aren’t sadists, so it may have to be enough to just know it exists.
Now consider politicians promising to harm some out group and people voting for them. It’s a combination of the first two: the politicians attempt to gain elected office by convincing people that the out group is evil or dangerous and promising to do something about it. The voters believe these cruel actions to be justice done to vicious criminals.
Yes. Return rate influences future product design.