When you are staring at the world screen wondering what race, track, car to use or do, for like, an hour.
When photo mode is no longer doing it for you.
When you know the top end of every car.
When you dump all your cars just to have something to do. (even the 'vader' cars)
When you start doing everything in b-spec cause you just can't drive the same tracks over and over without going insane.
When you watch your b-spec races instead of real races.
When you spend way way too much time trying to make the AI cars spin out.
When you give ice rallying just
one more shot, and then want to smash the machine because after 30 secs you remember why it's soooo horrible.
God, there's many more....
And after all this - -You fire it up and start a 9hr Endurance run just because...