During a break in class Bob Davis pulled out what had to be the second ugliest banana I ever saw. It was a deep dark brown, without a hint of yellow anywhere. As soon as he pulled it out the whole classroom went quiet and everyone stared at Bob wondering "is he really going to eat that thing?"
Professor Davis, never one to miss an opportunity to teach, looked up at the class and said:
When I was a kid, all the bananas at the fruit stands and grocery stores were brown. That is when they are at their ripest and taste best. The problem was they didn't have a very long shelf life. So the folks in the banana companies started an ad campaign to convince the public that yellow bananas were best. This would give them a longer shelf life and more time to get them to markets farther away from the ports.
He then took a bite of the banana. A true master teacher sensing a teachable moment and then teaching us an economics lesson in math class.