When we enter a negotiation we generally have one goal in mind: we want to reach a deal with the other side.  

It is our assumption that the other side of the table has the same goal  in mind. However, there will be situations in which this may not be the  case. As a negotiator, we need to understand that the other side may at  times be negotiating in bad faith. 

We have to be able to both realize this, and know how best to deal with the situation.