Who am I & How / why I am sometimes forced to act insanely

Here is that verse which you are searching for........

In the Vedic literature (Katha upanishad 1.3.3–4)
it is said:

“The individual is the passenger in the car of the material body, and
intelligence is the driver. Mind is the driving instrument, and the senses are
the horses. The self is thus the enjoyer or sufferer in the association of the
mind and senses. So it is understood by great thinkers.”

This verse has been summarised in Bhagvad gita as below verse



BG 6.34: For the mind is restless, turbulent, obstinate and very strong, OKṛṣṇa, and to subdue it, I think, is more difficult than controlling the wind.

BG 6.35: Lord Śrī Kṛṣṇa said: O mighty-armed son of Kuntī, it is undoubtedly very difficult to curb the restless mind, but it is possible by suitable practice and by detachment.

BG 6.36:  For one whose mind is unbridled, self-realization is difficult work.  But he whose mind is controlled and who strives by appropriate means is  assured of success. That is My opinion.

here's my answer for the knowing the mechanism:
Also answers the question : Every person has two sides, The ONE and The OTHER.one is the prime part of us ,other is evil.but why do we feel happy when we do evil practices influenced by OTHER? Why not we listen only to the ONE?