Why do cars have ashtrays if their drivers who smoke do not use them?

Okay! I see smokers driving and flicking their ashes out the windows and then when they finish the fags they throw them out the windows also. Why?
Have you ever been behind a smoker who throws a lit cigarette out of the window and it flies back on your windshield? Why are smokers so inconsiderate of others? Why don't they use the ashtray in their cars?
Then there are those who do use their ashtrays and when it gets full they dump it out the window. WHY?
Does nicotine do something to some smokers brains to make them think that they can litter the earth with the wastes of their nasty habits and it has no effect on the environment?