Some of the things that tend to get under my skin are negotiations that get down to the nickles and dimes. For instance, a Buyer and Seller arguing over a $50 rug, or a small $100 mirror, or who gets an ancient DVD player. Ugh.
I get that a dollar in your pocket is better than a dollar in someone elses pocket. We need to consider, however, how asking for that dollar might affect the deal as a whole. If the Seller gives in on the $50 rug, they may not have any interest in fixing a $100 problem uncovered in the home inspection. They might even decide to become tight lipped about the neighbors, the local grocery stores, or the local park. If you are buying a home, make sure you get a good deal. However, if you push too far know that it could come back to bite you later.
When working with a good agent, they will be able to tell you when you are about to go too far on negotiations. We are trained to know when to push and when not to. You might want to fore go the nickles and look for the dimes.