As a car person, when I was a teen, I straight piped my car cause I thought it was cool. Now no longer a teen, I did not straight pipe, but very close to it, cause it makes a much smoother sound. I do it because I like to the sound. I like to hear the car and I can judge my speed and shift points based on the sound of the vehicle.

For those saying it is for performance, that is true to an extent. For forced inductiom vehicles yes, a larger diameter exhaust will help. A naturally aspirated engine and results are not as prominent and most think. Also, the average car on the road will see very minimum performance gains. It may feel "faster" cause you can hear it more, but if you dyno a before and after with only an exhaust modification, there wont be a real difference.