I was a boss once, briefly.

The boss who said "you could do this in fewer lines" probably wants to say something but doesn't know what to say.

Of course you could do this in fewer lines. You could probably do it in one line and enter it in the Obfuscated Perl contest. So what?

I wouldn't worry about your boss's comment too much. It probably just means that he didn't see anything at all wrong with your code.