The constant need for 'approval' is another distinct feature of humans. It impacts our life in a variety of ways, and is a fundamental need. From the child looking for the approval of parents, to an officer waiting for the approval of the boss, there is no instance of a social transaction, where it cannot be seen. But, I have never come across an incident, where an animal waits for, or asks approval before proceeding with whatever is one's job.
It plays a significant part in our life. Many a great sage, as well as a lot of big criminals, owe their position, to the encouragement they received or the approval they missed in their formative years. No other want of the humans, be it food, clothing, or shelter, can cause such a significant and long standing effect on one's fortune. What is giving rise to this need? Where does it come from? How is it related to our metabolism?