T-shirts. The unmistakeable sign of an attitude. What attitude that might be is up to the wearer and for us to guess.
Some throw one on without any thought as to what it says or what it means, while others carefully pick one out that fits the statement they want to make.
In my ad hoc poll, most T-shirt wearers are conscious about the statement they are making. For me, I don't wear T-shirts out and about. I believe they are functional and use them for gardening, playing sports, working out, or lounging in the house on a weekend.