Turn Signals

Why is it so hard for people to use them? I've got better with my road rage issues, but people still find a way to provoke the feelings. I know that there will be people on this site that this blog relates to, so I expect one of you to be able to answer lol. It just drives me nuts how many stupid drivers who have no idea to get out of the passing lane if you're not passing anyone, use turning signals, and how to merge get on the interstate each day. It's not even a hard concept to grasp. The best are the people who go the damn speed limit in the passing lane, and then they get mad because you kind of ride them a little to get out of the way. I want a sign that says "hey moron, you're blocking 10 cars who want to pass" just so I can feel justified.