The world is similar to a large spider's web. Each strand, no matter how are apart, supports the others. They are all connected. What happens to one, happens to the whole. The same is true for everything on the planet, including the people.
People who are naturally happy and in good spirits tend to draw the same type of people to them. Those who harbor negativity tend to perpetuate the same type of reality. As part of the bigger picture, if you want a positive environment, you must fill it with positive things. Mothers with small children soon realize that if they are upset, their children soon become upset as well. If a mother smiles or laughs, their children will follow suit.
Scientists have studied examples of interconnectedness. One of the most well known experiments involved monkeys on the Japanese island of Koshima. After one monkey learned to wash the dirt off of a piece of food, she taught other monkeys. After several monkeys had learned how to perform the task, scientists realized that monkeys who had not been in contact with those who had washed the food, knew how to perform the task without instruction. This became known as the 100th monkey effect.
In both the domino effect and the 100th monkey effect, the results suggest a connection between each and everything on the planet, no matter how big or small. Although it may take long periods of time to complete the chain of events, the fact remains that we all influence the lives of our fellow man.