I hate no worries, thought it was cool when those aussie soaps were about.
used to say it all the time when working in a shop - customer says thanks and I'd say no worries
now when others do that I get really irritated, it's like saying yes I've helped you and don't mind because it didn't require much effort - does that make sense?
just in that context mostly I think. Guess I get grumpy when out shopping... think is mostly cos customer service is often lacking and I want to be out there working but can't!