Thinking about thinking is unnecessary. Thinking is same as worrying about something. When you do thinking, you are neither eating, nor sleeping or doing any physical work. Your body is at rest but your mind is not. No animal does too much thinking than what is necessary to interpret the inputs given by it's senses and correlate them to any self-driven actions needed. When people see you as lost in some thought, the first instinct they get is a negative feeling. They think you are worried about something or something wrong happened. There are no positive feelings you can get when you see your loved ones in deep thought.

Humans developed thinking in order to gain more complex correlations to help them interpret their sensual inputs, such as correlating that plants need water. But this has gone too far due to availability of free time for humans. Lot of unnecessary thinking, called philosophy and science, happened.

Human society always hated thinkers. Thinking was called witchcraft and banished. Thinking makes a person get detached from people and surroundings around them. You stopped processing input from your senses. You stopped interacting with world outside. Instead, you got busy interacting with your inside. People get scared and do not trust you anymore. They don't know what your thoughts are and how you are going to respond. Your thinking makes you an alien.

More importantly, thinking means you might not obey the commands from the community or group. Community requires simple thinking workers who think and act in expected ways, making it possible to have a strong community. Imagine some bees in a swarm do not follow the swarm movement, or ants in a line or fish in a school, birds in a flock. Community was always the real creature, not the individual humans. In many communities, individual persons do not have a name that is too distinct from family name. Family does the thinking, not individual people.