Mistakes in assessing one's own position and interests
Overconfidence, over simplification, exaggeration of conflict

Work toward understanding rather than positions
Evaluate and understand your own interests. 

Mistakes in reading the other party or assessing that party's positions and interests

• Opponent's "firmness" mistaken for rigidity

• Communication blocks or stereotyping make understanding difficult

Work toward understanding rather than positions
Learn and assess why the other party hold that view

A negotiation tactic (a dangerous but common one)

Guidelines to discourage

Thoughtful, bona fide and wide divergence in interests

May need to:

• Find a new approach,

• Widen the conflict,

• Change perspective, or

• Litigate or leave it unresolved

Conflict in worldview overtakes the conflict being negotiated

Refocus on the conflict being negotiated rather than the other's view of the work

Poor or incomplete communication

• Scope of negotiation was too narrow

• Conflict is exaggerated

Turn attention to communication directly then resume negotiation