Annoying sounds from cars at stop light

What causes the stereo in the car next to you at the stop light so loud and annoying with over the top bass and how can the driver stand it?

Its a status thing for a lot of younger, mostly guys.
My sons friend , who knew I was an audio lover, brought his pick up over to show me how cool it was that his new subwoofers could cause a quarter on top of the dash board to bounce 3 inches straight up, and flip heads to tails when the woofers were pumping out heavy rap.
That was several years ago. Maybe he grew up and wised up, or else is in the market for a hearing aid.
I came of age during the lste 60's-70's. Attended tons of rock concerts. Led Zeppelin, Fog hat, J Geils, etc. While seeing and hearing them live was a thrill at the time. I have a constant ringing in both ears for years now, that never lets up. Not sure the it was the smartest thing to do now.

You are correct about the sound waves. In your room they travel through the air, when they hit the sheetrock they are traveling through a different medium which has a different speed through which those waves travel, then air again 3.5" then the sheetrock again, then into the air again. Lots of moving parts. 
I was trying to discover the speed with which air travels through sheet rock but couldn't locate that info. I did find info that suggests that the resonance of sheet rock is about 70 hz which is probably why we hear louder bass on the other side of a wall and why that is so distorted. 

I would bet the MDF used in most speakers does much of the same.

I got the answer to the punks that have the loud bass and the fart can on the tail pipe. My truck is a Dodge Ram with a straight pipe on my Cummins. And if the truck isn't loud enough I turn on the exhaust brake. And with that because the noise and smell they shut there windows.

You are doing Gods work............except for the exhaust fumes........not sure he would approve....