I'm a roadie and a commuter. I don't think my mindset changes much between the two activities. I'm out there to have fun and enjoy some exercise, and when I am commuting I just happen to be going somewhere I have to be by bike. Situational awareness is a good thing to have. Other than that, I have the right to the roads, and any driver who doesn't like it can suck my scranus and write their state representative. I try to ride just like I would drive in terms of my general behavior..things like the laws of physics don't change (stopping distance, especially if riding with other people, friction, or lack there of on wet streets and/or painted lines) and do things like look ahead, plan for my next move/lane change/intersection and know where to go if things get hairy. And just like driving, I try to be proactive rather than reactive. I try to look out for more vulnerable users, like pedestrians. I would say there really isn't anything to it.