Some traders can be funny; imagine selling things at a higher rate to you that's even a relative, which simply means the trader only cares about himself and not the relationship shared.
For the first trader, the good experience you had was very insightful, and I love the fact that you purchased things there every time you were sent out to get things.
Some traders are greedy and they only think about the profit and they actually don't care about the relation with the customer. That's why they don't hesitate to cheat with customer.
!PIZZA