Confusing Street Signs

I spend Labor Day weekend with family and had a great time.  Unfortunately, every time I go visit family, it means I eventually have to drive back home.  Tonight I found myself driving with a ton of people who were obviously very confused about the meaning of two particular street signs: "Left Lane for Passing Only" and "Slower Traffic Keep Right."  I personally think they're pretty self-explanatory -- MOVE!!

I understand if you want to drive 50 mph in a 70 mph zone.  I understand if you like to drive slower once the sun goes down.  I even understand that sometimes you get on a freeway to avoid ONE traffic light.  I'm really ok with all of these, but why do you insist on driving in the left lane at the exact same speed as the car in the right lane?  Why is it that you insist on blocking all traffic behind you for miles? 

Anyways, in honor of those oh-so-confusing street signs, here are some truly confusing signs from around the web:

Photos by: www.majorlycool.com, www.thatsweird.net, jalopnik.com, strangepictures.net