[Lethal]

I have no idea.

[SmG 1mpAcT]

It's cheaper, easier, and less time consuming to put together a square box than a round one, also easier to grab the edges for transportation. When you think of a box, do you normally think of it as being round? No, so they would need to go out of their way to make round boxes.

[Lýn]

would be weird if there comming in round boxes lol

[Bunny]

Because squares are cool

[SmG Shiina]

Because why would they come in circle box's?

[SmG Tentacle]

probably because it's cheap to buy a bunch of cardboard and put the info on it. all they have to do is fold it and put the pizza in it. finding a circular box might be a lil difficult.

[UzzyFTW]

Must be cuz cheaper and shit

[Latenights]

To make it easier to get the pizza out of the box?

[Fabiozo]

It is easier to make than trying to produce round or many other shapes from cardboard.

[SmG FlasH™]

To make it easier to get the pizza out of the box?

How did no one think of this xDD

Other points are valid too, cheaper and easier to manufacture :)