I dont drive, but my mum always seems to get really annoyed at Private Reg Plates too, she says that people only have them to show off and to say they are rich, or to piss off other drivers behind them trying to figure out what the hell they are meant to mean.

She also gets a bit mad and starts swearing at other drivers alot when they get too close to the back of the car, so she drives really slow to piss them off.