Kindness and leniency in buying and selling.
Both the purchaser and the seller should deal with each other leniently and avoid harshness, debate on prices, etc.
This is proven by the following Hadeeth:
Jābir Ubn ‘Abdillāh (ABPWH) said that the Prophet (PBUH) said,
“May Allāh’s mercy be on him who is lenient when he buys, when he sells, and when he demands his money.”
(Al-Bukhāriy no. 2076)
The same applies when one asks for any of his rights. It is Sunnah to be lenient and tolerant as the Prophet (PBUH) said, “… and when he demands his money.”