Splashy cars

Here in the U.S., it's not unusual for people to put some messages on their car. Someone who wants to sell his car puts a 'FOR SALE' sign or directly scrawls the message with his phone number on the window. In my neighborhood, there are constantly more than 5 cars parked with 'ON SALE' sign on it, and most of these cars are still being used by the owners.
Also, the license plate is the other way of conveying messages. The popular type of license plate includes a heart-shaped or a star-shaped, or even a baby hand's-shaped symbol with a loved one's name or initials.
Yesterday, while driving in a mall parking lot, I ran across a parked car with a message saying "IT'S MY BIRTHDAY!" on its backside window.
It's cute and ostentatious, and I couldn't help taking a photo.
If the owner was there, I would have said to her "Good job and happy birthday!!"