My husband and I are avid cruisers, having cruised on NCL, Princess, Holland America, Carnival, MSC, Celebrity and even a Costa Caribbean cruise. We booked a back-to-back leaving Venice, going to Italy, Greece and Turkey and the 2nd leg back to Florida (36 days total). The first problem was the itinerary change AFTER we paid our final deposit and had already booked our airfare. We really wanted to see Turkey (2 stops) but they changed the itinerary and substituted Croatia and Montenegro. So, this wasn't a deal-breaker but we were disappointed as there were other ships that were going to Turkey.
Then, the 2nd problem - we were to embark in Venice but when we arrived at the port, the ship was not there due to weather. They ported the ship in Trieste and we had to be transported for a 2 hour coach ride to Trieste. The whole process was a nightmare (totally disorganized and a complete disregard for passenger comfort). We had to sit in the Venice terminal for 2 hours before our bus got there, with not even water being offered.
Third problem, once we got on the ship in Trieste, they closed the buffet line 10 minutes after we got there so food was limited and we had not eaten since breakfast. There were hundreds of passengers still being transported so I'm sure they were not happy when they got there with no food until dinner at 7:30.