You know you've played too much LFS when you know at least 10 server names off by heart, even when they are ones with combinations of symbols in the name, such as - ~< { [, so you don't need to look in the lists of servers.
Also, you know you've played too much LFS when you have multiple LFS's installed. I currently have 0.5Z, 0.5Z10 for testing, and 0.5Z with snowmod.
Oh yeah, you also know you have played too much lfs when you have taken note of exactly what speed your road car does in certian gears at certian revs, so you can replicte it in an xfg.
You know you played too much LFS when you can hold drifts on your first encounter with a cheapo rwd. Even with open diff.
oh and
You know you played too much LFS when you do a burnout and wait for them tyres to turn red. To your friends despair.