I want to make an introduction and share a bit about how I got here. I used to play Counter-Strike 1.6 back in 2009, and I was unbeatable. I would hit every shot to the head; for added fun, I would leave five bullets in the Deagle and go for 5x5 shots. I knew that five bullets would be enough to kill five people.
Matchmaking existed back then. In my country, there were systems where you could play competitive games. I was in the top 5. I thought I was better than others, that my reaction time was better. Everyone else was afraid to play against me. I can't explain that feeling, but I didn't even try to aim for the head; the bullets just went there, as if there were magnets on the enemies' heads. I didn't do any optimizations.
Later, I changed a lot on my PC, switched to Wi-Fi from LAN. Despite the Wi-Fi adapter having poor signal reception, shooting was still good when someone passed through it. Then I changed to another Wi-Fi adapter, moved the router further away, and shooting became unbearable. It took 15-30 bullets, entire magazines, to kill someone. It felt impossible to hit.
The point is, I see people discussing FPS, Hz, and thinking that certain shooting drills or tactics help. I find it amusing. The only thing that could affect accuracy is the internet and server. You can play with 60 FPS, 75 Hz, and no amount of training or 1000 FPS will help. Well, the only tweak I see now being mentioned is setting the priority to high on cs.exe. I used that back in 2008
, to be honest, it help, but I used realtime. And only after CS:GO was released and they started writing guides for it. 
I had the perfect config for CS 1.6, I used all the tweaks they talk about now ages ago. I want to somehow get back into Counter-Strike2 I only have 200 hours. But I see that I can't play normally because I just can't hit shots. Well, I hope there will be more internet tweaks here.