The Serrated Scribing Tool. When using measuring tape, If you don't have a way to mark the placement of your item, you can use the serrated edge to your advantage. Just press it down and scratch it back and forth.
Bottom of Wine Bottles. What's the purpose of the indentation at the bottom of your daily drink of choice? It's to relieve pressure while removing the cork. You'll notice that champagne bottles have an even larger one.
The Tiny Hole in iPhones. You'll notice a tiny hole between the lens and flash on your iPhone. It's a microphone! But aren't there already two others? The primary mic, the one you're used to seeing, is used for picking up a variety of noises, including your voice, while the secondary mic picks up ambient noise. There's a noise-canceling circuit that eliminates background noises and makes your voice sound clearer.
MacBook Charger Hooks. You've probably learned about this one when it went viral a few years ago but the hooks on your MacBook charger are there to help prevent you from breaking it. The next time you're putting it away, try wrapping it like this.
Bobby Pin Grooves. Most women are surprised to learn that the grooves actually face the bottom. When you think about it, it makes perfect sense. When they're planted on the bottom, they stay more secure.
The Hole on the Handles of Pots And Pans. Chefs sometimes use the hole to hang their pots and pans (great space saving tip) but you can also use it to leave your spoon as your dish simmers, assuming that it will fit.
The Arrow on Your Gas Gauge. How many times have you stopped at the gas station and forgotten which side you need to pump your gas? Well, this time you don't need to get out of your car to check. Look for the arrow to find out which side the fuel hatch is on.
Miniature Pocket and Rivets on Jeans. The smallest pocket in your jeans could barely fit your finger and that's because it was originally meant for a pocket watch. As for the rivets, they look like pointless buttons but they're actually there to reinforce the seams of the pockets. Pockets are vulnerable to rips so this greatly improves the item's endurance.
The Life-Saving Hole. According to an article published on The Independent, about 100 people die every year from choking on pen caps. You'll notice that BIC pens have hole at the tip of their lids. This doesn't only prevent it from leaking, it is also to comply with safety standards and reduce the "risk of children accidentally inhaling [them]."
Plastic Liners Under Bottle Caps. Check out the blue liner. This pressure seal is softer than the plastic used for the rest of the bottle and helps ensure the freshness and carbonation of your drink.
Treatments With Spikes. You're probably well aware of this one unless you found another method to open the tubes. When you purchase an OTC treatment, you might find a little spike beneath the lid. Flip it over and use it to puncture through the protective foil.
Bumps on the 'F' and 'J' Keys. These bumps help keep you in line with 10-finger typing. They indicate where the index fingers should rest so you can feel for them rather than looking down, especially if you've got a lot to type.
Indentation on Tic Tacs Lid. If you're a Tic Tac maniac like me, you might not find any use for this but if you've got some etiquette, use the lid as a dispenser like this.
The Hole at the Bottom of Padlocks. These little holes are for drainage and lubrication purposes. Take care of your padlocks and you won't have to buy a new one for years.
Extra Pieces of Fabric. Sometimes manufacturers will include a sample of fabric with your item of clothing so that you can test it with different laundering techniques. If it's a valuable piece, make sure to test it out so you don't ruin it.
Soda Can Tabs as Straw Holders. This design is simple yet so under used. Maybe you prefer to pour your drink out of a cup or feel the cool can on your lips, but next time you have a can of soda, try using the tab as a straw holder. All you have to do is pop it open and swivel the tab around and it should stay in place.
The Breather Hole in Airplane Windows. If you see a tiny hole in your window while flying, don't panic. The hole is there to regulate the amount of pressure that passes between the inner and outer panes.
Holes on the Side of Converse Shoes. Did you know that Converse Chuck Taylor All Stars were originally an elite basketball shoe? The holes on the sides are used for ventilation. Some folks also use it to pull the laces into a snugger fit.
Holes in Rulers. The next time you're holding a ruler, look for the hole or holes along the center axis. This is so you can hang the ruler up. Some rulers have more holes so you can store them in a three-ring binder.
The Purpose of Bi-Color Erasers. Notice how some erasers are soft and pink on one side and firm, gritty, and blue on the other? Some say that the blue is for erasing pen but that doesn't really work. The best answer we've found is that it is used for darker pencil marks and papers of heavy weight and different textures (grainy art paper, for example).