Rare, but they do exist. Yesterday at quarter after seven late afternoon, I got on to the 101 from the 92 junction in San Mateo and found myself behind some truck with a steady SUV on my left blind spot. Our velocity was pretty consistent, but I had the need to jump onto the left lane. Now Bay Area drivers generally respond differently to turn signals. They react as if it was some dare and speed up to either not give way to the guy with the blinkers or just completely pass them, and since I wanted to make a lane change, I figured I'd turn on my blinkers and provoke the SUV to pass me so I can get by. He (or She) instead slowed down a bit, so I moved over, waved 'thanks,' and also flashed my hazards once or twice in case they couldn't see me wave through the tinted glass.

SUV driver, I thank you.