Generally, I don't take blocking bike lanes terribly serious as I can look behind me to see if it's safe to shift over. What really bugs me is when the driver insists on getting back into his truck by walking around the front of it. Basically, there is no way to do that without stepping out blindly into the lane, and I've almost hit them doing this on my bike and in my car. It's something small children are taught not to do, yet here's a guy whose job requires him to get back in the truck dozens if not hundreds times a day completely doing it wrong.