cooking not plumbing

Ok, so I don't know a thing about plumbing, but I know a little about cooking.

Hot and cold feed, flow and return, gravity fed tank, dry header tank, it's all ballcocks to me, but do I deserve that look of contempt as he tried to explain ?

He was considerably happier half an hour earlier as he tucked into his roast beef and drank my red wine.

He didn't even look at the shower, plumbers !