Why do people have personalised number plates?
Musing on this I can only come up with a few answers:
Such is their vanity, that the fear that people will know the age of their car must be avoided.
The complexity of remembering random letters and numbers (eg for parking meters or forms) is too much of an intellectual strain.
They are overwhelmed by urges of self promotion/vanity such that sharing their name through any available avenue is a constant preoccupation.
So profound are their thoughts, insights that sharing them in a condensed means will help contribute to the enlightenment of the masses.