I used to believe that it was good to be smart, and the smart people were the ones who had great ideas. So I came up with some ideas, and then decided to believe in them very strongly, so that they would be great.
Later, I learned that believing strongly in big, bold ideas isn't so great when they're wrong. I noticed that the smartest people often considered and rejected many appealing ideas, and could explain why they were wrong. So I learned how to be very, very skeptical of ideas. I didn't have any big ones of my own, but I was sure that when I did, if it survived my own skepticism, it would be great.
Then I realized that in order to have great ideas, I needed to have any ideas - and that I could only make an idea better, if I knew what it was. My skepticism had taught me to throw away my ideas before they entered consciousness. So I learned how to entertain an idea before believing it, play with it, ask what about it wasn't quite right - and then try to mend its flaws instead of throwing it away.