That I wouldn't think of leaving home without that gizmo called a cell phone.
String theory (most of us had never heard of it).
Pluto deprived of its planet status and downgraded to "dwarf planet".
The rise and rise of Google.
US voters elected the country's first black president. (Will they now elect it's first woman?)
1. The United States of America got its first black president
2. Bruce Jenner became a woman
3. That the United States Supreme Court allowed same-sex marriages
4. Reality TV shows outnumber regular TV shows
Carrots improve eyesight
The internet would be possible
That the majority of people would still lack common sense and we wouldn't have destroyed ourselves, despite of this.
It's wrong to physically discipline your children.
That we have to worry about Islamic terrorists flying planes into buildings. That we can not trust the govt to be honest with us (Benghazi started because of a lame youtube video, and burning jet fuel can melt steel.... yah right...)