1. Realizing how little you actually know.
2. The whole problem with the world is that fools and fanatics are always so certain of themselves and wiser people so full of doubts.
3. The ability to transfer it to someone who lacks it.
4. Knowing when to shut up.
5. My father once told me that a sense of humor is the final test of intelligence.
I like to stick by that.
6. When your sarcasm is so high that people think you are stupid.
7. "Talent hits a target no one else can hit; Genius hits a target no one else can see."
8. Understanding that you can't change other peoples opinions by arguing with them...
No matter how "smart" you are, you're stupid if you think forcing your opinion will shame others into seeing things your way.
9. The smartest people I have come across were really really humble. Down-to-earth. They had their own Wikipedia page—and yet—never ever bragged about their achievements.
10. Have more than you show, speak less than you know.
—William Shakespeare. King Lear