I've stopped thinking others are stupid. I assume most people are smarter than me.

This reminds me of one of my favorite quotes:

  "Every man I meet is in some way my superior, and in that, I can learn from him."
  -Ralph Waldo Emerson

I used to find myself thinking others were less knowledgeable or less advanced than me in a lot of subject areas. Now I always remind myself that if such a great person could always find something in others better than himself, then there's absolutely no excuse for me.