To take responsibility of/for One’s Thoughts (question)

[Diana]

causing someone to commit suicide by putting bad thoughts in their head is wrong no matter how anyone spins it.

I don't think it's possible to cause someone to do this. I don't speak lightly on the subject.

We are all responsible for our own reactions. 

I do understand sentence: “Taking responsibility of/for your own actions/behavior”. However I’m a bit lost when it comes to Thoughts. 
How for example One can take “responsibility” of such Thoughts as:

Thinking badly about Other-Self
Thinking badly about Self

- and an oppositeness:

Thinking good about Other-Self
Thinking good about Self

I think we need to retrain ourselves. As far as I can tell, we as humans in human societies have been trained to think mostly negatively about everything. Just look at some sayings that are ubiquitous: money is the root of all evil; rock-a-bye baby on the treetop, when the bough breaks the cradle will fall; bleed like a stuck pig. It goes on and on with horrible imagery and negative viewpoints.

So it's a matter of being vigilant. Be the observer of yourself. A good question every time you catch yourself thinking something that gives you a twinge or you realize is negative is: Is that true? Is it true that that person who cut you off on the freeway is an a**hole? Is it true you are not attractive? That one is harder because we are so conditioned to societal standards. Whenever I catch myself in this mode, I look at myself in the mirror and name the things about my appearance that are great and I say it out loud.