Most of us have noticed that small, round indentation on the side of a plastic milk jug. I’ll admit it—I’ve stared at that little mystery circle more times than I can count. You know the one: the pushed-in circle that seems like it might be a factory slip-up or maybe even decorative. But it’s neither. That little dent has a very real—and very clever—purpose.
So, grab your cereal, pour some milk, and let’s reveal exactly why that dent exists.
