Yellow tumblers

We had a lot of Tupperware as my family grew up. One item I remember getting a lot of use was a set of six ounce tumblers. They were perfect for small children as they had sipper lids for when they were learning to use cups. They were also a good size for older kids, holding the right amount of milk or juice at meals.

They were red, blue, green, and yellow. And for reasons I can no longer remember, none of the kids ever wanted the yellow cup. They did not want it with a vengeance, to the point of trying to switch the cups at dinnertime place settings so they wouldn't get it. 

Of all the trivial things I had to anticipate dealing with as a parent while the kids grew, making them use a yellow tumbler would have never been high on my list of potential worry. It reached the point where we had to order our kids to drink from the yellow cup in turn. "Your brother had the yellow cup yesterday. You get it at dinner today!" was never the type of command I thought I'd waste parental authority on as a dad.

To this day I still have no idea what the problem was.