**Conflict of interest**

The authors declare no conflict of interest.

## **Thanks**

Thanks to every enthusiast, scholar, and researcher who came before me. Thanks to those who deal with emotions today, and to those who will do so in the future.

Everyone's contribution is a step forward in the path of knowledge. Thanks to every reader, without whom the effort of writing this chapter would have been futile. Ideologies separate us, and emotions bring us together.
