Business negotiation should never be approached as a fire sale, where, for example, there's always a deadline looming or some stubborn price point the customer must have: "I want to close next week," "I want to close at this price point," or "I need this percentage." These are not goals, but merely tactics. In fact, closing by a certain date is a trade and perhaps an important one, and shouldn't be an overall end goal for the dealmaker. Similarly, obtaining a certain price point is also a trade.
When you set a buyer tactic like one of these as a goal, instead of viewing it as the trading opportunity it presents, it ultimately sub-optimizes your deals. Bottom line, you have a higher chance of reaching a goal if you set one, so set it carefully. If your goal is "closing the deal by next week," you're likely to hit it, often at the expense of the value and/or price premiums left behind.