I do look at T shirts as a way of representing myself and my attitude, and I tend to choose them based on my mood that morning. Most of them have bicycles on them, or are in some way bicycle related. Very few are confrontational ("Jesus Would Ride a Bike" is possibly the most controversial of the lot). I generally get some good reactions; conversation starters, for sure. That said, I'm not sure that someone driving a car can actually read the T shirt of someone riding a bike, unless the print is truly large. Perhaps that rider's attitude gets communicated in other ways, too.