I'm a Denver native and I have a second home in the SF Bay Area. Colorado drivers are MUCH worse when it comes to allowing people to merge or change lanes. Most times, when I put on my blinker to change lanes, the driver slightly behind me in the lane I want to join speeds up and won't let me in. I think Bay Area drivers are among the most courteous I've ever dealt with. They have such soul-crushing traffic out there that people have learned it's easier for everyone if they all just cooperate.