Here is Friedman on Hayek from an Ebenstein interview from 1995:
Q: How would you describe Hayek personally?
A: In terms of his personal characteristics, Hayek was a very complicated personality. He was by no means a simple person. He was very outgoing in one sense but at the same time very private. He did not like criticism, but he never showed that he didn’t like criticism. His attitude under criticism, as I found, was to say: “Well, that’s a very interesting thing. At the moment, I am busy, but I’ll write to you about it more later.” And then he never would!
Friedman is extremely frank about Hayek in this interview, and repeatedly mentions that he objected to how Hayek treated his first wife. I have never seen Friedman be so negative, or for that matter so emotionally involved, and when it comes to The Fatal Conceit he simply avers: “It’s not up to Hayek at his best.”One has to wonder, was Hayek unhappy with criticism from Friedman, or was he just being polite in not engaging Friedman on topics he did not consider important or where he thought Friedman was way off.