A Mind meter
If we imagine a meter which showet, sum of ture and energy. sometimes it will show a high level, and sometimes a low level. When you drive a car and the petrol gauge shows an empty tank, you need to find a petrol station. If you see lower battery sign of your mobile or computer, you need to charge it quickly. Likewise in your life, when you are energized and happy, you can do anything and meet anyone. But some days when your mind energy is low, you don't want to talk to anyone. You would just like to be alone. You want to be free.