It's rarely that I take a note of what the other people's t-shirts say.
First of all, if you live in New York, you'd know that New Yorkers are too busy running around through the streets to not only notice the t-shirt texts, but to actually pause and read them. So, when I notice something, it's probably 'screamed' at me to be noticed. This is what happened with a t-shirt I've seen on a guy, wearing it casually with a leather motorcycle jacket over it, black jeans and sneakers. It looked very cool, as the t-shirt was gray with a black text on it, black jeans, grayish sneakers and black leather jacket - [kind of like - that look].
The whole look I loved and would have taken a photo of him, if I wasn't late for a movie screening. However, then I noticed what the t-shirt actually said...
...and mind me saying, even though he was wearing it - none of it applied to that particular person. He neither looked dumb, nor he looked ugly. So, now I'm shopping for the same t-shirt and have found the places, where you can get one as well!
I've also found some very good sites, where you can get t-shirts with some cool designs and texts. One of which I really like - Road Kill T-shirts - great for shopping for the presents!