A little story;
I worked in the first drive-through chemist opened in the UK; converted from a McDonalds.
One night, a guy pulled up in a Mrec, beautifully dressed, shirt, tie, suit, etc.
he asked for a burger and chips, with a coke.
I, for once, was speechless, and stuttered out, 'I am sorry....'
He repeated his order, looked at me, and asked why not.
Again, I said I was sorry, and he started getting quite angry.
Eventually I managed to stutter, 'because this is a chemist'
He was so embarrassed...and drove away.
True, and it happened nearly every night, for over three years...with different people.