6. Using time to negotiate via Email: Sometimes, not replying very fast can be used to indicate dis-interest by yourself. But, don't be caught in not replying quickly to the point where the other party feels like you don't care, and they need to move on. A fast response can indicate that you are either respecting their time and want to help move the deal along because it's important to you, or it can also mean that you want this deal MORE than they do, which is why you respond within minutes instead of days...and it may weaken your position.