Abstract from the linked study:

We review evidence showing that politeness taxes mental resources and creates confusion about what is truly meant during interactions. While this confusion can be useful in low-stakes situations, it can have negative, even dangerous consequences in high-stakes situations such as flying a plane in an emergency or helping a patient decide on a course of treatment. Unfortunately, high-stakes situations are especially conducive to politeness-based misunderstandings. Although policies that discourage politeness in high-stakes situations are undergoing empirical assessment, we suggest that research is needed on the nonverbal cues that help people disambiguate polite statements.