Politeness is described as a social norm, or a set of prescriptive social 'rules'. Many linguists have aimed to research politeness, including Brown and Levinson (1987), who developed their 'face theory' based on the principles of our desire to be liked and to not be imposed upon.
It is first important that you understand the concept of 'face'.
- Positive face is the desire to be appreciated and liked.
- Negative face is the desire to have freedom and not to be imposed upon.
- A Face Threatening Act (FTA) is an act which deliberately threatens the face needs of others.
We can then see how this relates to politeness.
Politeness is defined as using communicative strategies to create and maintain social harmony. This can be done in various ways:
In order to save face, people have the option to use politeness superstrategies  with FTAs:
Politeness superstrategies are determined by contextual factors:
Our aim in conversation is generally cooperative, so the more 'dangerous' we percieve our FTA to be, the higher number strategy we use.
Considering the theory from another perspective, we will now introduce you to impoliteness.
Impoliteness is defined as engaging in aggressive facework in particular contexts to cause social disruption. This can be done in various ways:
There are also impoliteness superstrategies  which can be used with FTAs: