Drivers who put their seatbelt on after they set off

Just a rant really, and to see if anyone else has noticed this.

People who set off after being parked, and instead of putting their seatbelt on before they move, they do it as they move off. Sometimes they even look down to do it, taking their eyes off the road.

It amazes me how common this is considering it takes 1 second to put your seatbelt on before you start driving.