Is an Undisciplined Mind the #1 source of Human Suffering?

I would say absolutely not.

If anything, a disciplined mind is capable of inflicting great suffering.

Soldiers and terrorists alike are greatly disciplined in their ways of thinking, and the result is death.

Political zealots likewise discipline their thinking, which results in oppressive actions against those who do not follow their agenda.

I don't know what the #1 source of human suffering is, but it is certainly not an undisciplined mind.

Disciplined or undisciplined , one thing I will tell you that the mind a function of the brain mass is gone wildly rampant with out control , every body things that one is what the mind is able of , that one is what one thinks .I say we are all wrong ... our brains are instruments of actions and decisions and we all should learn to control our thinking mind , is the thinking mind in our self's full of egos that create the loves and atrocities around the world , we have to recognize that our soul and spirit is extremely more intelligent than our mind full brains and our souls are devoid of egos , we all have souls and yes we are able to tap into the knowledge of our souls if we really wan to and allow it to grow over the brain thinking that has taken over . When we allow the soul to rationalize and make decisions over the brain thinking , you will find human peace have finally arrived !!

No there is no such thing as an undisciplined mind.Human interaction sees to the training of the mind. The only undisciplined minds are the ones that are insane.So in the context of your question .The answer is irrationality.

I agree with Buddha, it's desire. Desire for the world to be different than it is. Is desire caused by an undisciplined mind? You could say that, sure.

It's also the fact the people can't understand that life has no meaning. They "desire" meaning and there simply isn't any.

No. I believe the source of personal suffering to be a mind that is devoid of curiousity. Without curiousity and the desire to "know", one has nothing except one's own narcissistic self.