Another side of japanese bike culture

Past few years, Japanese custom bike culture have been getting attention,,Zero engineering, chicara,,so and so.. they are really inspiring.

There is another side of japanese bike's called BO-SO-ZOKU,,( reckless driving tribe,,I guess) mostly teenagers from 14 to 20 yrs old,, when they hit 20yrs old,, they usually retire from that,,why? I don't know,, I wasn't one..
anyway,, they don't go fast. they make noise by twisting throttle rapidly ,even making melody.,they call it CALL.and carry air horn honking ,, they are still around all over japan..
it's really annoying when they come around your house,, but it's kinda funny..