Limerence… A word made up by psychiatrist Dorothy Tennov describing an emotional state most people call love. The one thing that Tennov doesn’t mention but I think it would be possible to extend to concept of limerence not only to people but also to companies, nations, groups, ideas, and software programs.
The other word that I’ve used a few times is passion
Passion… This is an interesting word because the root of passion is suffering for a higher cause, and I think that passion and limerence go together. The concept of passion is important in international relations because how a dispute turns out often depends on how much a party is willing to suffer for its goals.