I have not sailed on the Magica, but have sailed on some of Costa's ships. Sailing Costa in Europe has a flavor all its own. Expect a heavy International crowd (many Italians) that have different customs than Americans do. If you are expecting the same ambiance that you would get on say, a Caribbean cruise, then it might seem awful to you. If you treasure unique and different experiences, then you might well love it.
There is smoking, loud conversations, different expectations from the dining experience and different food. It would only be awful if you did not understand the difference you will experience.
Take the time to learn some Italian before your cruise and you will have a blast.