It has been an arms race to add new features and even though Carnival has not tried to claim the "world's biggest cruise ship" title, it has added new, bolder features to its ship. Its Excel-class ships offer the Bolt roller coaster, a first-of-its-kind attraction at sea, and each new ship pushes the bar further.

Dry dock schedule changes can force cruise lines to revise cruise itineraries or cancel sailings to take the ship out of service during a time when it was scheduled to sail. For p

Cruise passengers seem especially vulnerable to various scams that have been going around. That's at least partially because many cruises are not fully paid for upfront. In many cases, passengers may make a down payment,

Sometimes, cruise lines can negotiate better deals for their passengers when it comes to the fees various countries charge for port visits. That's because the cruise line will be bringing so many people to that destination, that it has some leverage because it could opt to visit that port less often.

This might be one of the most annoying parts of cruising, and one cruise line has been more aggressive in fixing it than the other.