For the vast majority of people who insist on not wearing masks, the expected benefits of not wearing masks are generally greater than the expected losses caused by this behavior. Here are some typical examples: 1. During the epidemic period, even in areas with high epidemic risk level, at the entrances of various public places (such as shopping malls, office buildings, residential areas, etc.), there will still be quarrels or conflicts between intruders and staff who do not wear masks. For intruders who forget to wear or carry a mask, following the rules of wearing a mask means that they need to get a mask first: they either spend money on a mask or spend time and kindness asking people around them to send a mask. In most cases, insisting on forced entry without wearing a mask does not require spending money, time or human feelings. Without the protection of compulsory force, it is difficult for staff to persuade, stop or even warn intruders of substantial losses. Even if a typical woman like "Australian Runner" is punished, on the whole, similar punishment only affects a very small number of unruly people. Comparing the stakes, it is profitable to insist on breaking in without wearing a mask. However, when inspectors become police, soldiers and other coercive groups, the behavior of intruders who are still "head iron" will be significantly reduced. When coercive forces intervene, the interests are reversed. Forced entry is not only unprofitable, but even severely punished. 2. Preventive medicine believes that for a certain type of infectious disease, if the proportion of people vaccinated reaches a certain value, even those who have not been vaccinated are hard to be infected again. For example, for measles, this value is considered to be 92%~95%. Similarly, if the vast majority of people wear masks, even if a few people don't wear masks, it will be difficult for the COVID-19 epidemic to spread widely, because the probability of COVID-19 in the environment is very low. At this time, the benefits of not wearing a mask include more comfortable face and smoother breathing, but the risk required is very low. However, this kind of behavior has the risk of damaging the public interest and is not worth promoting.