Potential customers thinking a quarter-pounder would hit the spot were disappointed when they wheeled into the McDonald’s restaurant in Muskego Monday night. There weren’t enough workers to cook the chicken nuggets and french fries. A sign reading, “Sorry lobby is closed due to low staff,” was placed on one of the doors and the drive-thru was shut down also. Several workers had called that day to say they couldn’t come in. Young staff members quitting and students returning to school made it hard to full all the needed positions.