Is there a reason why someone's mentality is always negative or dark? What could be the reason?

There may be some reason, our very few past life experiences may affect to our present and future life, so we should understand and realize that those things was facts and it happened why it is happened like that way, and don't generalize everything is happening to us will be negative, like that , so think like " I am doing a great thing and If I do things like great it will be fine, try to think positively, when we are thinking negatively we get a negative result and If we think positively we will get positive result, so past life is a fact, but in present and future we can do things positively, and collect only the reason and try to solve or avoid those mistakes again. Thank you, and God bless you with great love , by your sister.

Yes, Regarding to the behavioral theory, negative mentality can occur due to (Learned helplessness). When a human endures painful situations where he cant cope with or avoid, he fails to cope with new situations where such behavior would likely be effective.

Cognitive theory explains the negative mentality as negative automatic thoughts, generated by dysfunctional beliefs about the self and the others.

Self-schemata are considered to be grounded in the present and based on past experiences. Memories are framed in the light of one's self-conception. For example, people who have positive self-schemata selectively attend to flattering information and selectively ignore unflattering information, with the consequence that flattering information is subject to deeper encoding, and therefore superior recall. Even when encoding is equally strong for positive and negative feedback, positive feedback is more likely to be recalled. Moreover, memories may even be distorted to become more favorable, people typically remember exam grades as having been better than they actually were.

However, when people have negative self views, memories are generally biased in ways that validate the negative self-schema, people with low self-esteem, for instance, are prone to remember more negative information about themselves than positive information, memory tends to be biased in a way that validates the agent's pre existing self-schema.

 

Good evening Lina, I hope you are well.

As far as I know after years of clinical practice in a multicultural context (being my caseload in excess of 1500 clients/patients), I have no reason to believe that there is a specific reason for this).

 

It is just a matter of personality, I suppose.

Obviously, when younger, I was much more 'sunny' than now in my sixties (but, yet much less calm and self-balanced ... allegedly :)

Hope this helps, and good luck with your job, Lina !