I understand that the line was very short--just me, with one person in front of me. I understand that this is usually not cause to open another register. However, it was a very hot day and I had just walked a mile. I was dripping with sweat, tired, and shaky as I waited patiently in line while you lounged around the front of the store drinking a cold bottle of water.
You could have offered to ring me up. You *especially* could have called me over when you finally did open your register because two more people had approached the checkout area.