What you say you are isn't what you actually are.

Nothing says this quite as directly as a personalised number plate.  They are relatively cheap, and proliferate in Melbourne. To wit:

The owner probably thought putting a number plate that says "panther" (but in txt spk so it is only 6 lttrs) on his MR2 would make him (and it's usually a him) seem mysterious, sleek, and effortlessly cool.

Sadly that is not the only reaction that can be had.  Ho hum.  Don't try too hard is my advice.