Most of us don't give a damn about this little things, but apart knowing what it is meant and why it is there it might also bring you cash (who wants to be a "moninaire" Lol.
Without much wasting time Lego...

1.
The Little Hole In The Side Of A Pen
At a first glance, it might strike you as just a design but it is there for a reason and meant to serve a good purpose. Without the hole, a pen will be completely airtight and as you write and use the ink, the pressure will fall preventing the ink from flowing to the tip and eventually the pen will cease to write although there is still ink in it.
On highlands or in planes where the pressure is lower, a pen with no hole can explode soiling your attire with ink. The hole equalizes the pressure in the pen to allow it to write. So the next time you see it, you should know it is not just there for fun

2.
An Extra Piece Of Fabric
Those who usually buy from “bend down boutiques” might not relate to this but if you’re the type who always buy brand new clothing from boutiques, you will notice there is a piece of fabric with a button on it tucked in the pocket of either a shirt or trousers. Many people actually think it is meant for patching when you get the attire torn but that’s far from it. It is actually meant for you to use to test how it will react with detergents when using your washing machine. So what you need to do with is by washing it to see how it will fade before washing the main attire to prevent colors from sipping into other fabrics.

3.
The Little Hole In A Pen Cap
You might be wondering why there is a little hole at the tip of the cap of your pen and you might not see the importance of it or you might assume it is just a design, but it really serves a significant purpose.
Without that hole, whenever you close your pen, the air trapped in the cap and the inserting of the pen will create pressure which will push the ink out of the tip of the pen preventing it from writing and secondly, it is meant to prevent death if you accidentally swallow the cap. In case you swallow a pen cap, the hole will help you breathe easily till it is surgically removed, without it, many people would have choked on it and died.

4.
Little Hole In A Padlock
When you check the bottom of your padlock, you will notice there is a little hole close to where you put the key to unlocking the padlock. This might mean nothing to you but it is there for a purpose. The hole is meant for you to grease your padlock in case it gets rusty and gets stuck and you need to get oil in it. It is also meant to drain water that gets trapped in the padlock. If your padlock does not have the hole, then it is made out of stainless steel and it is supposed to be used indoors to prevent water from getting in.

5.
The Punt Under Wine Bottles
The dimple under wine bottles known as Punt are not just there for decoration purposes, it is actually there to help the wine sparkle while in storage. Had it not been because of the punt under wine bottles, the bottle will exert pressure from the wine and explode.

6.
The Blue Side Of An Eraser
You remember those erasers we used back in school which had one side to be blue and the other to be red? Back in school, we were told the blue is meant for erasing pen writings, most of us tried it and it obviously didn’t work, we ended up tearing our books. This is because the blue side is not meant for that, it is actually meant for erasing pencil writings on hard surfaces while the red side was meant for erasing pencil writings on soft surfaces. Now you have it, you can teach it to your children so they don’t repeat your mistake.

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7.
The Bump At The End Of A Laptop Cable
The bump at the end of your laptop cable known as ferrite beads is not there to distract you or mess up your day. It is not just there for fun but serves a good purpose. It is there to prevent interference in the cable.

8. The Hole In Airplane Windows
If you’ve flown on a plane before and sat close to the window, you will notice there is a small hole in the plastic glass covering the windows. That hole is meant to allow air to flow into the plane and also to regulate the pressure in the plane.

Bilabong:
4.
Little Hole In A Padlock
When you check the bottom of your padlock, you will notice there is a little hole close to where you put the key to unlocking the padlock. This might mean nothing to you but it is there for a purpose. The hole is meant for you to grease your padlock in case it gets rusty and gets stuck and you need to get oil in it. It is also meant to drain water that gets trapped in the padlock. If your padlock does not have the hole, then it is made out of stainless steel and it is supposed to be used indoors to prevent water from getting in.

me I always put the grease directly into where the key is inserted. lol. thanks for this. Front page please