While I was cleaning my room and flattening boxes for recycling, I noticed a neat feature on the shoe box of my most recently purchased pair of Keds. A tab in the cardboard box design that allows a person to easily flatten & recycle the box without tearing, cutting or pulling tape and staples.
It took a minute to notice the affordance and the proper interaction — I even ended up ripping one corner apart before noticing it — but once I learned it, I was amazed at the simplicity. Not as jaw-dropping as some other packaging design, but this attention to detail is micro-ingenuity that I admire. This box design allow manufacturers to save on materials (tape, cardboard, metal staples) simply by leaning on the human mind to learn a new pattern for interaction.