Some of it's due to the people you play in general, as stats and SBMM still can't give an accurate picture of what someone is capable of. Example, I have a terrible combat rating and my K/D is nothing to write home about, but I am ranked in the top 5% of my preferred game mode. So some people with lower stats will actually outperform them, and you might get matched against them. then there is the personal consistency. It's really hard to notice this unless you are recording and watching gameplay footage, but over the course of a play session you will deviate from your norms. You might start approaching choke points differently, or deciding when to challenge in better or worse situations. As time goes on, you start getting different thresholds for your actions, and you will act accordingly. We all get that to a degree. And lastly...take a break from time to time. I'm not one of those 'don't play the game all day' people, but your brain needs a chance to reset itself to it's neutral state periodically. If you play some good games, and you see yourself starting to decline a bit, it's time to take 5. Get a drink with some light, simple sugars and a small bite to eat (handful of pretzel sticks, etc.) and think about some plays you've made in various games. Take your time, eat and drink slowly, and just go back to even ground. then try again, and see the change. Once you see yourself outside of your normal patterns, you need to take a second to relax, analyze, and reset so you can know what's happening and avoid reinforcing bad habits. This is what works for me, hopefully it helps someone else as well.