"Show and discuss your code, without emotional attachment."

Not my experience. I have always had emotional attachment to my code. My love for my code is what has enabled me to grow. Passion is half the battle.

I got the impression that he meant that it's easier to receive constructive feedback when you're less attached. Not every line of your code is perfect, so if you're able to stand back a bit from your code then you'll be more open to improvements. It's something I still have trouble with sometimes, but I usually try to be less attached to my code.