In Germany you have to pass on the left lane and switch back to the right lane as soon as there's no one left to pass. Same applies to Autobahns with 6 or more lanes, you have to change right anytime you can't pass more cars on that lane. Oh, and all exits (there is one exemption somewhere in Germany I think) are on the right side.
I personally hate driving on the left lane. I usually drive at 130-140kph (80-86 mph), sometimes up to about 160kph (100mph) when passing fast-but-too-slow vehicles. Usually 15 seconds after I change to the left lane to pass someone, there's someone behind me approaching me at an estimated speed of 200+kmh (124mph), almost crashing into my car, then driving only a few meters behind me.