In a negotiation, the less the other person knows about you, the better off you are. The more you know about them, the stronger your bargaining power. Of course, some information must be exchanged in the give and take of bargaining.
The problem is that what you say and what you show may be used against you if it reveals your weaknesses. How much you choose to reveal is a matter of business judgment. But less is better than more in most cases.
Salespeople often make a similar kind of mistake when they tell a buyer how anxious they are to win a contract or renew an order because business is slow or inventories are high.
We know they do so to convince the buyer that they will get a good price and exceptional service if the order is awarded. The problem is that they may raise the expectation of the buyer so much that a substantial discount of ten to fifteen percent is seen as unacceptable.
People tend to talk too much during negotiations. Go into your next negotiation with the idea that less talking means better results for you.