What is the biggest challenge to negotiation?

Thanks 

In my opinion the most challenging matter in negotiation is when one of the parties does not want to give any kind of compromise 

to understand the situation of other party. If you will understand them you will surely come to a win win solution.

The biggest challenge to negotiation is when individuals are not ready to understand the second party at all. There are individuals who only think about their interests and tend to ignore the interest and needs of the other.

Biggest challenge is  to have trust. Another challenge is to understand that  negotiation will be mutually benefitted to all the parties.

let part to take other parts

Thank you. Biggest challenge of a negotiation is if one party will not satisfy.