Our only issue to date was water in the cabin from above (maybe two decks from what I heard through the grape vine). We were presented a bottle of wine at dinner Friday night (not one we are necessarily fond of - pursers desk should have checked with our waiter
). We documented the situation on our comment card (in the space available) and got $100 off our sign-and-sail.
I wrote Carnival because I wanted to highlight the inefficiency of the purser's information desk - no explanation as to the source of the problem, weren't very helpful during the problem, but also wanted to highlight how effective we thought housekeeping was as well as other crew with whom we were impressed. Got the a promise of future discount that I don't know if we'll be able to use (a matter of timing - not abandoning Carnival).