Oh, Gary boys...
In the UK, they "show off" by driving around in circles in town centres in their modified (aka ruined) Fiat Puntos with their windows down, and playing hip-hop/rap loud enough to interfere with the functioning of the international space station.
Their favourite activities include; harassing women, harassing fat people, swearing at old people, throwing litter out of the car, and narrowly missing small children as they floor the gas for the sake of about 10 yards, before slamming on the breaks on reaching traffic.
Fortunately, a fair few do write off their cars, usually by stupidly smashing into inanimate objects like lamposts/fellow Garys.