But it was his fault. And he should be more careful with customers.
Whether they complain or not doesn't really matter. I didn't because my new boss was sitting next to me and I didn't want to make a fuss.
But he shouldn't put anybody in this situation or react rudely when pointed out the fact he committed a mistake.
People don't complain for different reasons and it's not a good customer orientation if someone thinks customers should point to the problem directly or otherwise their complaints aren't legitimate.
But it's also the reason why I don't complain anymore, instead write bad reviews. Businesses don't normally react good to direct criticism.