"[I]n close relationships, when you identify with the other person, expressing disappointment can be an effective negotiating strategy. It avoids the negative connotations of anger and protects the ongoing relationship, which could explain why it’s often used (to great effect) in parent-child bargaining. The research also serves as a warning: don’t expect disappointment to have any sway on negotiations with strangers or when your opponent is acting on behalf of others. In those situations, threats or hard bargaining tactics are your safest bet."
- Sebastian Bailey, Using Emotion To Win Negotiations
http://www.forbes.com/sites/sebastianbailey/2013/10/22/using-emotion-to-win-negotiations/

"[W]hile some people boil over in negotiations, others freeze up."
- Kimberlyn Leary, Julianna Pillemer, and Michael Wheeler, Negotiating with Emotion
http://hbr.org/2013/01/negotiating-with-emotion/ar/1

“Anger can be an effective negotiating tool, but only as a calculated act, never as a reaction.”
– Mark McCormack

“The most difficult thing in any negotiation, almost, is making sure that you strip it of the emotion and deal with the facts. And there was a considerable challenge to that here and understandably so.”
- Howard Baker

Taking things personally
“During a negotiation, it would be wise not to take anything personally. If you leave personalities out of it, you will be able to see opportunities more objectively.”
– Brian Koslow

#MainMessageForToday
Be careful with emotion in negotiation. For example, it is better not to get angry. But, anger can be an effective negotiation strategy.

Both parties should see eye to eye....

Song 'Eye To Eye' by Tevin Campbell:
https://youtu.be/TAuCpdCn3gc