Look around you. There are a lot of things you don't know about everyday items that you've been using your whole life. Now, look at the items below. Most people can't figure out the purpose of these items. But when you find out what they're each for, it'll blow you away!
That "12M" symbol represents 12 months. This is used to tell the user the shelf-life of the cosmetics they are using.
So, what is this hole in between the lens and flash? It's actually a microphone which helps to deliver clear audio during all functions. So no, it isn't a CIA listening device. Well, I guess it could be.
The bottom of the knife is extremely dull on purpose. It allows you to change blades safely without too much fear of losing a finger.
Those little ridges on your Reynolds Wrap are for keeping the roll in place to make it easier to rip off.
That little "57" on the Heinz ketchup bottle is not for decoration. It's actually showing the perfect place to squeeze the bottle to get a nice stream of ketchup.
That ridge in a lollipop not only works as a whistle (try it) but it's designed to make sure the candy stays in place firmly. Nobody wants their lollipop falling on the ground.
Those symbols tell you the type of plastic each plastic container is made out of. The symbol on the bottom of the container lets you know if it's recyclable, can be put in a dishwasher or not, and if it is microwave safe.
Those plastic rings on bottle caps aren't just there to prevent spills. They actually keep the carbonation inside the soda to keep them from going flat.
Most headphone jacks have two lines. These are used to make sure audio can be heard in both ears.
That little metal plate on the bottom of the stapler actually bends staples when rotated. Why you would want to do that is an even bigger question!