Negativists spread a bad mood. Their negative mood is highly contagious. If a negativist succeeds in convincing others that everything is wrong, they stop feeling isolated and also experience satisfaction from their own influence. Therefore, it is best not to let oneself be influenced by their behavior. By doing this, you protect your mental health and avoid having your energy drained, and your colleague will increase the chance that if his negativity does not have any response, he will try to change his behavior.

"Martin constantly complains, criticizes everything, and nothing is good enough for him. He gets the work done, but the comments around it. Everyone likes to complain once in a while, but this is too much. Negative reactions to everything that happens.
We all know that Martin doesn't have it easy in life and we tried to help him, make a concession, and listen to him. The problem is that there is nothing like gratitude or even occasional positive emotion from him. Most of the time, he looks angry, grumpy, and dismissively. He responds critically or derisively to all suggestions, tasks or requests. It's quite exhausting to work with him."

How can anyone be so negative? The causes can be different. Quite often, such a person is deeply dissatisfied with their own life and does not believe in the possibility of positive change. And so he takes every opportunity to confirm that "everything is wrong" and that he is just a victim of a hostile world. He wants to make sure that it's not his fault, nothing can be done about it, and others see it the same way.