3. Feeling of Community
On Disney cruises, we can almost guarantee that the other people aboard your ship will start to feel like extended family after a few days. By the end, you won't even want to say goodbye to your waiters or stateroom attendant, or even the people who joined your table every night as part of the dining rotation.
If you happen to join a "fish extender" gift-exchange group before the trip, you could make connections with other voyagers that will last a lifetime.