Rude buyer towards sales person - seeing the other side

In this case, I think that both people with in effect salesmen and no one was rude.
The dealer had a bottom price, and was negotiating a profit.
The customer was setting a bottom price and was negotiating a great deal.
The dealer was stating prices he thought was reasonable, and the customer was stating what prices he thought was reasonable.
Both or either sides could walk away at any time without any regrets.
Where is their a problem?