I think its when people buy crap for there car that really doesn't suit it, i.e 50ft wide bodykits (ok slight exageration) therefore ruining the look of the car rather than enhancing it i.e angel eyes, maybe a custom respray.
Lots of young people modify their car, some i.e the chavs spend a small amount and buy poor fitting kits as they want their money spent to be noticed, others the style icons spend what they have on quality parts.
But with the never ending saga of rising petrol and the usual costs of tax, insurance etc, many people dont have the money to spend on 19" alloy wheels, lambo doors, engine conversions and a full on custom respray!
And whoever can and does actually have them done is very lucky indeed!
Totally of topic sorry.