As someone who does customer service as a "fun" side job, it's people that like to complain for the sake of complaining that are truly annoying. Rather than addressing the source of the problem, just complain to whomever happens to be around, even if it's not their fault or issue.

I'm glad that getting on someone's case for what they do makes you feel better. Very cool.

Yeah, I know you don't care and tough s**t to me. Very cool.

Cheers.