The type of staff that they employ in their high street shops are largely untrained poorly educated Traceys and Kevins (with apologies to people have those names!) who have often never travelled further than Blackpool or Majorca.
Perhaps they have been unable to afford themselves and their families the luxury of travel on the measly £12k a year they get as opposed to the six figure salary i'm sure you're likely to be on. With that attitude it is no wonder they don't bother to treat you as you feel you deserve.