To have made the mistake of thinking...

[DarthInvader]

...that an "air guitar" was an actual TYPE of guitar?!

I mean, there's such a thing as an air rifle, isn't there???

Name changed on this, as several RL people have enjoyed endless merriment as a result of know about this particular misconception.

So please make me feel better and tell me about anything you used to believe, which was only corrected in adult life.

Nope, I think you are on your own there.

Erm, do you point at airoplanes when they fly over you? Just wondering............

This just gave me a good giggle! Can't think of anything I used to believe but I can be pretty dim sometimes so I'm sure something will come to me soon. Iggypup reminded me though that I once told my friend to avoid stepping on a dead bird on the path in front of us - she looked up into the sky.

Someone once fooled me into thinking they had stuck a spoon to the ceiling using static. I was too short to see the piece of blu tack they had used...

Would you belive that a windy winter blows the summer round more quickly?
A friend of mine did.

There's also such a thing as an electric guitar too, so I suppose you could in theory have one powered by air or something ......

A few years ago a CD was released called 'Air Guitar Anthems' or some such and on the adverts they promised 'a free air guitar with every CD purchased'. You're apparently not alone OP because shops were inundated with requests for the free air guitar at the checkouts.

YANBU.

I thought an articulated lorry was called an 'ARCTIC' because it contained frozen food. It was only recently whist reading my infant son the book 'terrific trucks' that i realised my mistake; I am 43.

I thought that gas works that were not full just hadn't finished being built...I was amazed when I found out they go up and down. I'm usually pretty sensible - honestly!

Well, years ago someone told me that the royal family didn't fart because they had their "clappers" removed

that was in my 30's

When I was about 6 I was mortified to see a dead worm at the bottom of a display swimming pool in a garden centre. So my dad, not wantiing me to be upset, told me that worms could survive underwater, and after closing time he'd wriggle up the side and off into the plants.

Fast forward 10 years to a GCSE biology lesson at school and (I can't remember the exact subject matter) this comes up and I say that worms are amphibious. When asked to explain how I knew this, I suddenly had that sinking feeling that nothing my parents had ever told me could be relied upon to be the truth.

My DS2 asked for an air guitar one Christmas

But to be fair, he was only 3

HTH