Boarded at Malaga, crossed Atlantic for first time and found it very relaxing but not boring. There was plenty to do and see on board. The trouble began at the first Caribbean island stop - Antigua. There were two ships in port together, swamping the facilities available. This happened more often than not on the rest of the cruise- surely it is not beyond the wit of the cruise lines to arrange their schedules to avoid it? There was also the first of the totally artificial "tourist villages" - all almost identical, all full of the same Costa-sponsored jewellery and other shops. I suspect that if one checked the ownership of these places, Costa would figure. These are frequently designed so that disembarking passengers were forced to walk through them, accosted at each shop by insistent staff. At Grand Turk this was ALL that was available as the town was some distance away and closed on a Sunday! There is minimal contact with the real culture and people.
The tours sold by the ship were overpriced and often poor - the coral in the "reefs" to which we were taken was usually dead or dying and the fish very few. The bus tour of Belize was an hour of viewing decrepit houses in junk and garbage-filled gardens, the bus a battered and uncomfortable ex-Dallas Greyhound coach. When we asked where the city centre was our guide told us that there was not one - certainly there are only a few, sad shops. Most passengers were back on board hours before sailing time, having found nothing of interest to do, see or visit.
In Miami it was actually cheaper for four of us to share a taxi to go to the Dolphin Mall than to take Costa's tour to the same destination. In Jamaica, after docking at a ramshackle pier (we later found it was for loading bauxite!!) with corrugated metal sheets blowing gently in the breeze, we boarded the tour bus to see the only thing worth visiting, the waterfalls. On arrival there was a major shouting match between passengers who had been told that entry fee was included in the price and the crew of the bus (caught in the middle) who said it was not. Most passengers demanded the return of their money and walked back or took a taxi. We found on all the islands that frequent and amusing local buses had a network of routes at an absolutely minimum fare, usually a dollar.
Ocho Rios in Jamaica was a squalid example of what 30 years of no maintenance can achieve coupled with demanding beggars and street vendors.
All in all the Caribbean is over-cruised and some ports of call not worth a visit. Others such as Grand Cayman should not be missed.