I used to be quite anal (!) and somehow think it was my duty to tell everyone if they made a mistake by blasting on my horn (!) whenever I saw, for example, someone awkwardly attempting a tricky maneouver in a back alley (!) or something.
But now, I just think 'screw it', if people want to drive like idiots, then I let Darwin's theories take care of them. As long as I am driving safely and can avoid any danger, that's all that matters to me now.
(am I getting old?!)