This chart describes how English speakers in Britain communicate. Sometimes what they say is not exactly what they mean!
The chart describes language that is used, however, it does depend on the social situation. If you are with friends in a café, then you will need to speak as directly as possible.
A boss talking to an employee must also communicate in clear language.
Personally, I prefer people to speak directly, so everyone understands what is being said. However, there are situations when people need to make a point in a sensitive way.
I think it is important to be aware of the language used in this chart, as you may hear these phrases being used by an English speaker :)
Please note this table can also be used by people from the USA as they also need help to understand how British people use these phrases!