If the storyteller has reasonable motivation to withhold information.
If the storyteller has an underlying agenda.
Explanation:
These characteristics do not necessarily imply that bias exists in a text. It is possible for an author to have these characteristics and still be able to write an objective, unbiased text. However, this becomes less likely as more of these characteristics are present. Identifying these situations in text can allow the reader to identify instances of bias that might affect the quality of the text.
