Deborah Tannen (the linguist and author of "The Argument Culture") tells a story about how bringing in lawyers to write up an informal agreement derailed it completely.

Some companies, however, referred the matter to their attorneys so a contract could be written. In no case where attorneys became involved-- mine as well as theirs-- could we reach an agreement on working together... The adversarial nature of the legal process had polarized us beyond repair.

https://www9.georgetown.edu/faculty/tannend/argsake.htm