Rode my carbon fiber go-fast bike to work today. I'm planning a little road ride after work. About half way to work I noticed I picked up a goathead thorn in my front tire. (My usual commuter bikes have mtb wheels and slime.) I stopped to look at it. It was sort of on the side of the tire and the tire was holding air so I decided to leave it. Got to work ok. Pulled the goathead out and.... whooosh. I'll have to change a flat later.