When we praise others, we ourselves enjoy the benefits of complimenting others.
For example, if a girlfriend buys a new piece of clothing and asks the boy if he looks good in it? The right amount of praise from a guy to a girl will not only make his girlfriend happy, but will also further promote the intimacy between the two. However, there are also studies that have found that belittling others may do us a favor. For example, in order to appear confident and decisive in the course of the presentation, the speaker will be advised to try to imagine the audience as someone wearing only underwear. The core meaning of this is:In a new social group, if one's partner is viewed in a way that devalues the authority of another, it will give the impression of confidence and decisiveness. 
February** Dynamic Incentive Program
Why is this happening? The premise of this phenomenon is that people can easily and intuitively judge the agency characteristics of others. AgencyRefers to traits such as dominance, self-confidence, and decisiveness associated with the pursuit of personal achievement or the demonstration of personal ability. Active behaviorThis characteristic refers to the behavior that this trait prompts people to produce, that is, the behavior located in the upper part of the interpersonal ring model (see Figure 1). 
Fig.1 Interpersonal ring modelFrom this diagram, we can see that dominant behaviors are divided into three types: dominant behaviors (high agency and medium community), hostile dominant behaviors (high agency and low community), and friendly dominant behaviors (high agency and high community). The reason for this phenomenon is that it can be usedEvolutionary Game TheorywithComplementarity of interpersonal behaviorto explain. In evolutionary game theory, the emergence of leadership is described as a social dilemma in which individuals can choose whether to "lead" or "follow." Strategies that aim to lead lead lead to greater potential benefits, such as access to more resources or partners. However, it is also a riskier strategy, as it can be highly conflicted and costly if other individuals also aim to lead. It's like a battle between tigers for the throne, and the loser will eventually lose everything and end up being expelled. 
Thus, according to game theory, there should be a direct link between perception, social behavior, and leadership emergence. When people believe that few of their team members have the will and ability to become leaders, this should minimize the perceived risk of their choice to become a leader. As a result, people's decisions to pursue leadership positions depend in part on the perceptions of others. Interpersonal complementarity is the belief that the interaction of two people is usually characterized by a complementary patternIn this model, the dominance of one actor leads to the submissiveness of the other partner, and vice versa. To put it simply, when you are in a position of strength or put yourself in a position of strength, the less risk you can perceive. Degrading others is just a way to make yourself look like you're strong.
Research confirms that belittling others can do you a favorRichard Rau and his friends hypothesize that people who think others are less motivated will exhibit active behavior.
Here's a quick example: Xiao Ming is a transfer student, and when he enters the class for the first time to introduce himself, when he finds that his classmates are quiet and shy (low motivation), Xiao Ming will tend to show confidence and introduce himself loudly (high agency). 
And if you find that your classmates are very good at performing and have hot eyes (high agency), Xiao Ming may feel that he tries to avoid antagonizing these people and shows low agency. That is, perceiving others and perceiving oneself occur at the same time. We are both perceivers and perceived. In Richard Rau et al.1, he conducted an experiment with a group of first-year psychology students who were about to enter college. As soon as the freshmen stepped on campus, they were taken to the lecture hall by the researchers (meeting the experimental conditions of "zero acquaintances"). They were asked to introduce themselves on stage in turn, and after each introduced himself, the others graded him. The results show that perceiving the low agency of others contributes to a reputation for high agency. Those who perceive others as having low agency will introduce themselves in an arrogant way (hostile dominant behavior patterns). The results of Study 2 by Richard Rau et al. are consistent with Study 1. In general, it means that subjects who think that others have low motivation will be judged by others as highly motivated people later. This is because these subjects have more hostile dominant behaviors during the experiment, and their levels of aggression, arrogance, and self-confidence become higher, leading to an increase in agency reputation. 
So back to the example of the speech at the beginning of the article - one can think of the audience as someone wearing only underwear during the speech as a way to boost self-confidence. This suggestion is not confirmed by empirical studies. But the work of Richard Rau et al. provides some evidence for this mechanism of behaviorSo it's not impossible that "belittling others will do us good." Once it has been confirmed that the hostile dominant behavior of the individual is an important part of the mechanism, then we can assume that:The reason why people don't show confidence when they give speeches is because they perceive the agency of the audience. In this case, people are unable to express themselves, so they can reduce the image of the audience to make themselves imagine that they have a high level of agency in the eyes of others, and thus relieve tension.