Person A buys an item from Person B. Person A given the wrong address- right house & street name, wrong postcode.
Person A gets a taxi over, and is dropped off a 10 minute walk from actual location due to this.
Person A requests a discount on the item due to inconvenience. Person A offers them half the amount of the requested discount instead of the full amount.
Neither Person A or Person B are happy with the outcome 
Who is BU?
YABU: person A unreasonable
YANBU: person B unreasonable