This video is a prime example of how attitudes change. It seems we go just go from stupid to stupid all the time.
digg.com/video/this-1967-british-news-report-that-interviewed-drunk-drivers-before-it-became-illegal-is-bonkers
Another example is passive smoking. Obviously stupid and horrible to think we just smoked freely inside, thinking it was fine to breathe in smoke.
Fossil fueled cars will likely be the next as will idling cars outside of schools but I wonder what else we'll be scratching our heads over in future.