What do you think is the emotion that joins up all human beings on Earth? (I'm not going to talk about animals)

I personally think it’s not love. Love is an elusive emotion and anyways people can live all their life without love, (and I’m not saying that it is because humans live too little). No, I’m talking about fear. It’s the most elusive emotion too, but to STUDY. If a person doesn’t feel fear or doesn’t have a personal relationship with fear, it’s because it’s not a human being or a person with a brain sufficiently developed. And, I underline, EVERYONE reacts differently to the fear they feel inside. Chemically, electrically (brain mechanism), even instinctively and with what words to say, what to think, etc. Psychologists have defined accurately love, but not fear. They are at a loss to what to do. And if you still don’t believe me, look to all the information findable here: https://en.wikipedia.org/wiki/Fear_processing_in_the_brain But enough stalling. I want to hear your opinions. What do you think about all this?