Let's do a quick count; Who among us here who plays, or at least used to play, First-Person Shooter games with their mouse Y-axis inverted? Raise your hand if you're one of them, I'll wait.
Done? Great. I hope I'm not the only one raising their hand looking like a retard.
Yeah, I used to play FPS game with the inverted mouse option ticked on, and I totally was not able to play it otherwise. Believe me, I tried a lot back then, but the only thing I get was increased miss rate and death counts. It really caused some problem when I'm playing with my friends and switching players each time one of us dies, even more than when someone's eating some cheese potato chips.
So why do some people use the inverted mouse mode? Well, according to the most popular theory, it is because of most First Person games back then were Flight Simulators. Star Wars: X-Wing and TIE Fighter, Terminal Velocity and Descent, to name several of the famous ones. The reason is because they are simulating the feeling of flying inside a cockpit of an aircrat, where the pilot uses flight sticks to control their movement. Even the Mechwarrior series uses this same setting, because the 'Mechs are also controlled by using the same stick.
Pulling back the stick makes the aircraft go upwards, while pushing it down makes it go downwards. So in order to emulate (simulate?) that sensation, default flight simulators controls inverts the Y-axis for the mouse, thus making old timey gamers feel more comfortable playing FPS games with the said control method.
Sometimes, they also feel more comfortable with these beautiful pixels
Does it mean that people using inverted mouse settings have better skills since they are more closer to reality than the 'normal' players? Nope, it's just the same. The only difference is their natural habit to do it. This is why nobody ever bothered to learn how to use inverted mouse unless they really have to or have a gun pointed on their head, there's nothing special about it. And if you're wondering how do we feel when trying to use the normal setting for the first time, try playing the Surgeon Simulator, or at least play using the inverted mouse setting for a bit; that's exactly how it is.
The first flight sim that I play without using the inverted mouse setting was Freelancer, and it's because that there was no option to turn it on in the first place. But the game can be played in third-person view, so there was less problems then because I don't need to think to pull up my "neck" in order to look up. And the combat was basically to "follow the red dotted circle and shoot at it", which makes it really easy for me to cope with.
The one game that finally got me off the inverted mouse habit was Dragon Nest, an MMORPG with a non-targeting combat system to maintain a complete control of the player character. So, unlike the usual MMORPGs, you need to actually aim your attacks and not just pressing multiple skill buttons like a rythm game. It is feature that I honestly prefer more, really.
The game has no inverted mouse option, but I was enjoying it so much that I just keep going, despite stumbling a lot at the first time. As time passed, I managed to actually convert to the 'normal' mode. But the consequence is that I can no longer play with the inverted mouse option on, so the game managed to rob me of my 'unique' trait that separated me from other gamers. And since I'm quitting the game, maybe I should say thank you for it.
And especially for adding a cute loli character in my pool, and introducing me to a very talented singer
So by the end of the day, people using the normal setting and the inverted mouse is basically the same, they each just play differently than the other. I hope you 'inverted' comrades never felt bad about your 'unique'ness, and know that you could actually adapt to normal if you really want to.