First, human beings are all of the same species. Their bodies, their autonomic nervous systems, their hormones, and their sense organs resemble each other in structure and in use, and there is no doubt that these brains, autonomic nervous systems, hormones, and sense organs are essential to emotion.
Second, in order to survive in the world, human beings must be able to appreciate changes in the environment that have important consequences for their well-being, and they must be able to respond to these changes effectively. They must cope with immediate perils and take advantage of immediate opportunities, and they must be concerned with the various threats and opportunities that are not so immediate. There are commonalities in the kinds of external events that make life better or worse for human beings, just as there are commonalities in our internal equipment. Like all species, humans are built to respond to the things that matter, and the way humans do it is by emotion. Enormous loud objects rapidly bearing down on us must be escaped, and fear provides the motivating force. Encouraging behavior from an attractive member of the opposite sex comes to evoke desire in most people at about the time they reach sexual maturity. If our species is to survive, our babies must grow up, and so their mothers must love them. When we need something, and see an opportunity to get it, we feel hopeful, perhaps challenged if we also perceive an obstacle, and are moved to go after it. When we get it, we feel relief or joy. Although physical and social environments around the world are all different from each other, they all include novelty, hazard, opportunity, attack, gratification, and loss. These are changes that people must deal with, and these are the kinds of events that generate emotion. To ignore them would make learning impossible, and would jeopardize life itself.
To respond appropriately to these consequential events, we must perceive them fairly accurately and recognize their importance. If our brains are similar, and our perceptions are accurate, it follows that this kind of important environmental event will be a universal antecedent of emotion across societies, although not necessarily among all individuals within any particular society. There are universal antecedents to emotion insofar as there are universal human needs and goals. (By "universal" I mean, as most psychologists do, "very general." There may be societies that deviate from these very abstract propositions in some respects, but "almost universal" is the best most social psychologists dare to aspire to.