Let's be honest, most of us buy a Kinder Egg because of the toy inside, right?
In each little chocolate treat there's a small surprise toy which sometimes requires assembly.
And now you might not have noticed this, but there's something about the colour of the capsule.
The shell is always a yellow colour in every Kinder Egg Surprise.
While some people might already know this, one Twitter account couldn't believe it.
The Today Years Old page posted an image of the Kinder Egg Surprise toy and the inside of an actual egg.
Did you know why the Kinder Egg toy is yellow? Tell us how you feel below...
It said: "It took me 22 years to realise that the toy capsule is yellow to represent an egg yolk and that makes so much sense."
And since it was shared, the post garnered 340 likes and dozens of retweets.
One commented: "Wowwww."
Another wrote: "I'm still not over me knowing this."
While a third commented: "It makes so much sense!"
However, a fourth Twitter user seemed to already know the news, adding: "Uhhh... duh."
And if that's blown your mind, don't worry we've got more.
Previously, the same Twitter account revealed the flap on a McDonald's fries box has a hidden use.
It showed how there is a designated flap on the back of the container where you can put your dip of choice.
Yes that means you can dunk your fries into your ketchup or mayo without having to spread it all over the place.
Since the hack was shared, more than 1,000 users retweeted it, while 1,300 liked it.
One said: "I am shook."