The biggest nightmare for a programmer :
PLEASE REVIEW MY CODE

Why?

I prefer having code reviews.

Code reviews are nice

1. You get to show your superiority (whether it makes sense or not)
2. You learn new things which you might not if you were not reviewing
3. You learn from coders who code better than you, thereby improving your self-review skills

Biggest nightmare is when no code reviews are in place and any old bollocks gets committed.

This alone is not a nightmare. You are exaggerating.
I would be DELIGHTED if anyone asked me to perform a review on their code.

@asgs
4. You're not responsible alone when you fuck up