It is a shop.
You clicked a shop. I am not going to insult your intelligence by explaining what happens next.
Everything here is something I called you on the internet. People bought them. I remain baffled.
Things I have called you
Every one of these was said out loud in an episode before it was ever printed on anything. That is the whole rule and it is why they work.

Bargain-Bin Genius Hat
The verdict across the front, so everybody knows before you open your mouth. • 26% cotton,...

Bargain-Bin Genius Mug
For the morning coffee of somebody who is about to explain something they read once. •...

Bargain-Bin Genius Sticker
A sticker of a man holding a sticker, and he is holding it at you. •...

Bargain-Bin Genius T-Shirt
For anybody who knows one fact about the dinosaurs and has been dining out on it...

Decorative Gourd Mug
Sits there. Looks like something. Does nothing. Hand-lettered insult mug from Man Explains Everything. • Ceramic...

Decorative Gourd Sticker
The decorative gourd insult as a hand-lettered vinyl sticker. Peak autumn, permanently. • Vinyl with satin...
There is also a book.
One hundred and ninety-nine things you have got wrong. Every one of them sourced, with the sources printed in the back so you can prove it to whoever doubted you.
It is also a colouring book. That was the printing bill, not an artistic decision, and I would rather tell you that than pretend otherwise.
Go on thenWhat is this
I explain things. History and geology and whatever else somebody asked about, on video, for nothing, and I am rude throughout.
Nothing here was invented for a shirt. Every line was said out loud in an episode first. That order is the entire reason any of it is funny.
The videos stay free. They were free before there was a shop and they will be free if you never buy anything.