First, we must recognize that people can hold different cultural norms and, therefore, can consider different topics to be “safe” and “appropriate.” People from different countries can have different cultural norms, but so can different people within a country as diverse as the United States. Therefore, we cannot always know for sure that a given topic will be acceptable for discussion in any particular social setting.
There are some topics that will generally be seen as “safe” and “appropriate,” particularly if the social group is made up of the “right” people. Three examples of such topics are discussions of sports, of work, and of friends and acquaintances. All of these topics can be very safe and appropriate. They are typically of interest to a large number of people and they are not generally seen as distasteful. One must, however, be somewhat careful in talking about these subjects as they may be boring to some people. There are people who do not care about sports. People who do not work in a particular job may become bored if a group is “talking shop.” If you are talking about friends and acquaintances, people who do not know these people may become bored as well.
It is always appropriate to make sure that the topic of conversation changes around from time to time so that everyone can be included even if they have different interests. However, it is generally safe to talk about sports, one’s job, or friends and acquaintances that one has in common with the people with whom one is speaking.