For our honeymoon we cruised on Carnival Imagination for four days to Cozumel. This is part of a series of anecdotes on the experience.

The basic appeal of a cruise is that it’s an all-inclusive getaway. With your ticket you get round-trip transportation to one or more vacation destinations, lodging, meals, and a variety of entertainment. Just choose a sail date and a ship and your entire vacation is planned.

The reality is that quite a lot isn’t included. Alcohol is clearly the biggest seller on board, running $7 to $10 for most drinks and available everywhere. Soda, espresso, and other beverages are also upsells — only tap water, coffee, lemonade, and iced tea are included. And with a 15% gratuity added automatically to every purchase, ubiquitous waiters are effectively working on commission to sell those drinks.

Not thirsty? Buy a commemorative picture of your vacation taken in the dining room, on the pier, or in front of staged sets and backdrops throughout the ship. A 5×7″ print costs $10 with a variety of framing options and photo albums available. Or order a heart-shaped “Happy Honeymoon” cake, visit the on-board shops to buy gold chains by the inch, book a shore excursion, schedule a massage at the spa, or play some Blackjack at the casino.

We never felt pressured to make any purchases, but the opportunity was omnipresent. We had budgeted some extra expenses and we went through about $40 just in coffees, sodas, and bottled water to drink in Mexico. Other guests, though, seemed to have sticker shock upon seeing their final bill on debarkation day. On a cashless ship where room keys serve as charge cards, it must be easy to get carried away.

This all sounds much more unpleasant than it really is. Most of the ship’s amenities really are included. When we wanted to see a Broadway-style show in the Dynasty Lounge, we just walked in and found a place to sit. We watched two comedians at the comedy club, attended an art auction and a dance performance, and walked in and out of the restaurants about a hundred times. We played several rounds of miniature golf, relaxed in hot tubs, and read books in deck chairs overlooking the ocean. We took a salsa dance lesson and lost spectacularly at a dozen different trivia games.

The real basic appeal of cruising turns out to be that there’s no set agenda, nowhere to be, and nothing important to get done. We didn’t forfeit tickets or give up our seats if we chose to relax by the pool instead of attending a show, and that simple idea is the essential ingredient for a relaxing vacation.