Now I've seen everything in the brazen petty chiseling department!
In the U. S., eggs are sold by size based on the average for a carton, so a dozen "large" eggs might have noticeable variation in the size of individual eggs. It is not unusual for me to find a couple of "extra large" eggs in the carton. Recently, as I waited to get my eggs, a shopper ahead of me spent a few minutes going through the eggs and swapping them, presumably to get the largest eggs for herself. This was not in a poor neighborhood, but at an upscale grocery in a nice neighborhood.
Can anyone top this?