You know you're a LFS fanatic when your choice of TV is dictated by whether or not it has a VGA input so you can play LFS on a bigger screen.
You know you're a LFS fanatic when after a long LFS racing session you get in your car, push down on the clutch and realize the car is an automatic
You know you're a LFS fanatic when after you realize that your car is an automatic you estimate when the car will change gears, back off the throttle while pushing the imaginary clutch while shifting the imaginary manual gear box.
You know you're a LFS fanatic when you enter a corner in real life and the lines separating the lanes seem completely redundant and illogical as you follow the best racing line for the particular corner.