However, if you need to resolve a major disagreement, and then make sure you prepare thoroughly. Become a highly effective leader; minimize stress; improve decision making; maximize your personal effectiveness; and much, much more. For a negotiation to be 'win-win', both parties should feel positive about the negotiation once it's over. This helps people keep good working relationships afterwards. This governs the style of the negotiation - histrionics and displays of emotion are clearly inappropriate because they undermine the rational basis of the negotiation and because they bring a manipulative aspect to them.

Despite this, emotion can be an important subject of discussion because people's emotional needs must fairly be met. If emotion is not discussed where it needs to be, then the agreement reached can be unsatisfactory and temporary. Be as detached as possible when discussing your own emotions - perhaps discuss them as if they belong to someone else.

Ultimately, both sides should feel comfortable with the final solution if the...

Equally, you should expect that if they need to fulfill some part of a deal in which you have "won," they may be uncooperative and legalistic about the way they do this.
References

David Vickrey, "Counter Speculation, Auctions, and Competitive Sealed Tenders," the Journal of Finance, March 1961, pp. 9-37. http://www.careerwomen.com/pr_Negotiation_Tips.jsp

Harold Strawbridge, Philadelphia, USA

Gary M. Lawrence, Due Diligence in Business Transactions, (Law Journal Press 1994)

http://safari.oreilly.com/9780136007364/ch16

Cultures and Organizations: Software of the Mind - Geert Hofstede - 304 pages [New Ed.] (23 May, 1994) HarperCollins

Ian Steedman (1987). "Reservation price and reservation demand," the New Palgrave: A Dictionary of Economics, v. 4, pp. 158-59.