I love cruises. As someone else already mentioned, they're like inexpensive all-inclusive hotels (often less than $100/night per person) with food, entertainment, sports, and so on.
However, my brother hates them. He didn't like the feeling of being surrounded by other people all the time, and even the shore excursions (which can be very private if you just wander off on your own) weren't enough of an escape.
I really suggest you try an inexpensive 7 day cruise yourself to find out if it's for you!