Staff working in the service industry are often greeted by unruly Karen customers who march in like they own the place, demanding discounts and ordering them around. Often because of poor management, the staff are forced to deal with the impolite attitude quietly inside their heads, as opposed to talking back and standing up for themselves. In this case, OP was working as a barista at a coffee shop where they served such a Karen customer, who happened to be a regular. Karen was manageable up un…