You should be familiar with the phrase "keep right, pass left" or something similar. Many states require that you stay in the right lane unless you're passing. This is likely one of my biggest pet peeves, and I've noticed that increasingly, the left lane is becoming the new right lane.
It's 5:30pm, and I'll be on my way home on the highway, three lanes wide, sometimes clogged, sometimes medium traffic, when I'll be doing the speed limit and I come upon a vehicle doing at least 10mph slower, occupying the left lane. Usually I'll give the driver a chance to move over (a few seconds at least, if not more)- that way they have adequate time to check their rear view. If the lane immediately to the right is free, sometimes they'll move over, but more often, they won't.
Cell phones, food distractions, whatever the case, sitting in the left lane but to pass is illegal, and perhaps its time we cut down on those who simply occupy the lane with no intentions of passing. I can't be the only one bothered, my local Department of Transportation has been adding signs that clearly state the left lane is for passing. We even have huge electronic signs that also request slower drivers to keep right, but do they work? Hardly.
I guess it's just something I'll have to deal with until people understand what the left lane is actually for. I typically just accelerate around these people and try to make them aware of whats going on. Many times, I'll look back and see the driver I just passed moving over. Great! I'm glad some get it.
At least we aren't in Europe where passing on the right is a pretty major offense. The huge difference is that people over there understand lane usage and passing on the right is not necessary. Here it's becoming more and more necessary. I don't think its too much to ask drivers to stay aware of their surroundings and move lanes if they find themselves holding up traffic.
So- are you a left lane addict, or do you only use it to pass?