some reasons:
you know you´ve played too much Lfs when: you are in road, you see some nice place without any house or anything on it, just trees, and you start thinking on make a real Blackwood circuit on it (xD).
you know you´ve played too much Lfs when: you try to look for the Shift+a combo when you want make your IRL car sound better.
you know you´ve played too much Lfs when: you look in the Oil pressure gauge thinking that it will show your fps.
Adolfo Herrera.