It turns out that Xbox controller buttons are actually very different in size to one another.
Just yesterday on September 6, the post on the Reddit gaming subreddit forum took off, with well over 20,000 upvotes a day later. The post itself shows the different sizes of the Xbox buttons, as they reach further down into the controller itself than one might initially think.
In the comments, people have attempted to explain why this is actually the case. It turns out that every Xbox controller, whether it be for the Xbox One, Xbox Series X, or Xbox Series S, all have two printed circuit boards, otherwise known as PCBs, housed within them.
These two PCBs are placed one on top of the other. The contacts for the A, X, and Y buttons on the Xbox controller are positioned over the top PCB, while the B button is positioned over the PCB that's lower down within the controller, hence why it's longer as it has further to reach to the circuit board sitting underneath.
It's also worth remembering why the buttons are all slanted in such a way. The B button is more slanted than the other interfaces because it's closer to the curved edge of the Xbox controller, whereas A, X, and Y are all closer to the middle of the controller, and are therefore on a much flatter surface than the former button.
It's a really neat bit of trivia for Xbox owners, and something that would no doubt have remained hidden had people not taken apart their Xbox controller to either mod or fix them.
However far the buttons go in, here's how to use an Xbox One controller on PC.