Please don't drive.
I know there is no logical reason why this would be so but it would seem that wearing hats while driving, or even having a hat in your car, makes you a really bad, inconsiderate, ignorant and/or stupid driver.
Don't believe me? Test the theory for yourself. Whenever you see someone cruising along the freeway doing 37km below the speed limit - check their head. If they are not wearing a hat then you will undoubtedly spot it on the shelf behind the back seat. If you see someone who indicates in the completely opposite way through a round about than what is described in the road rules (as well as the rules of common sense), you can bet your bottom dollar they're wearing a hat.
It would also seem that the type of hat directly affects the level of uselessness of the driver. Baseball caps typically relate to those who feel they are the most important person on the road (and doubly so if they are also a P-plater) while a straw hat or an akubra is your Sunday driver who forgets that there is anyone else on the road at all.
So, my plea is clear. If you intend to have a hat in the car, don't plan to take your car out of the drive way. Plleeeeeeeeeeeeeaaaaaassssseeeeeeeee!
Bareheaded and safely conscientious on the roads.