In Bhagwat Geeta Lord Shri Krishna talks a lot about controlling your mind.
Like this saying from Bhagavad Gita: “For him who has conquered the mind, the mind is the best of friends; but for one who has failed to do so, his mind will remain the greatest enemy.”
But my question is why God made mind so cunning and hard to control at first place?
Why didn't he designed the mind in the way that it may automatically act to serve the God or stay away from all such wrong doings?
Trying to give a simplified answer to a complex and fundamental question, Acharyas have addressed this in their philosophical treatises. Pardon my limitations here.
The jivatma's desire to enjoy sense objects is one of the reason mind exists. Mind is difficult to control because it gets habituated to the sense objects, and gets into a tangle of desires related to sense gratification. Quoting relevant verses from Gita.
In Gita 15.9 we find
The living entity, thus taking another gross body, obtains a certain type of ear, eye, tongue, nose and sense of touch, which are grouped about the mind. He thus enjoys a particular set of sense objects.
and in Gita 2.62, we find
While contemplating the objects of the senses, a person develops attachment for them, and from such attachment lust develops, and from lust anger arises.
and in Gita 16.12, we find,
Bound by a network of hundreds of thousands of desires and absorbed in lust and anger,
If the jivatma sincerely desires to serve Bhagavan, Krishna will definitely provide the needed help, and help orient the mind in that direction. There is abundant support in Shruti, Smriti and Acharyas for the "doctrine of grace" which is a large subject, hence I am not quoting those here.
Please note that there is no such shloka in Bhagavad-gita. you have mixed up couple of shlokas. also to say god made this or that is creationism theory which is not from our shashtras. in bhagavad-gita atma is said to be unborn, eternal, indestructible, immutable. also prakriti and purusha are both anadi - unoriginated.
Looking at your question, it seems that you do not know much about dharma or shashtras.
Anyway, lets start with mind. one needs to understand fully what this mind is. to do that a simple technique is to look at everything which is around you with wide-vision and then see the 'seer' who is observing all this. Also see how all that one thinks is in mind. this needs to be explained in more detail.
Every living being has Mana or Mind. Beyond that exist Soul/Atma. Jiv Atma (Soul) is eternal and divine rather part of Brahm himself so always pure. https://www.vedabase.com/en/bg/3/42
On other hand Mind is result of Prakriti/Maya. Who ever you are, whatever yours like or dislikes is result of Bhavani (Maya). She is responsible of living being body and their Mind. She is the one decide for what you will desire or what not.
[http://astroveda.wikidot.com/printer--friendly//durga-saptashati look at section Nature of mother]
Basically she controls the mind. Gita teach you to go beyond Mind and reach your ultimate form.
As we heard things like we are on autopilot.
Why Mind is so difficult to control?
It is difficult because of the society and culture we are living in. Look around you these Bollywood, Sex, Race for the money and getting success. It will never let your mind stay in single place.
and that is why my friend you should control your thoughts and mind. Because if you control it you can guide it to right path or this mind will guide you to your destruction.
