Megan McArdle, on why she was wrong about the war in Iraq, and What She Has Learned from Her Chastening Experience:
The biggest thing I've learned is simple humility.
Megan McArdle, replying to those who are less than satisfied with her account of this error:
I have no particular interest in the opinions of my harsher critics on this topic; the only interesting criticisms of my thought process so far have been made by me.
Shazam!
Also, what Roy said.