Bad Service checkers atlas road

Had a demeaning experience at Checkers Atlas road in bonaero park.i was following an old lady on the que ,as soon as she left i started offloading my trolley placing the items on the till. The cashier by the name of Thina without greeting me started scanning the items , only when she was almost done she said ‘HI PLASTIC?’ Wow ! I proceeded with payment and left. There was a white gentle man who was with a toddler .i overheard the same lady greeting this customer with respect ‘Hi Sir how are you? would you like a plastic’? Why are we treated differently? Why do we get different kind of service.