Yes, you are absolutely right. The stall holders have a rapport / relationship with their regular customers. Sometimes, they reserve the good stuff for them, and sometimes will tell them that the items which the customers want to buy are 'not so fresh today', and ask if they can wait till the next visit. Sometimes, they will recommend customers - or if you ask them - they will tell you how to cook the items, the best method and ingredients to go with it. This, you will never find in the supermarkets. Cheers!