The only bad cruise I had was the Carnival Splendour in Nov 2010 when it caught fire the 1st day out. We made the best of it. It could of been worse.
I believe all cruises are fun and if you expect too much is when you run into disappointment. Go, enjoy yourself and be happy you are on vacation exploring something new.
Cant' wait for my 1st cruise on the east coast. Will be taking the Dream in April 2013 to the Carribean...our 1st time back on a ship since the fire.