This is interesting to me because I feel exactly the opposite!
If it's a business I feel it's their job to get as much of my money as possible for the item, and it's my job to hold onto as much as possible. I will bargain more cut throat with a business. They have high mark ups and their business will not live or die on the strength of this one deal. A business also has no emotional attachment to the item where in a personal negotiation the seller has owned this machine or their parent or grandparent has often owned the machine and they feel a connection to it. I will be more gentle in my negotiations and more generous in my offer with a person.