Your cruise ship room -- or cabin -- is your personal haven at sea. You can go there to escape the pool deck and buffet crowds, or invite friends over for a lively party. Curl up on the balcony with a good book, or turn out the lights and drift to sleep rocked by the waves. You can decorate it, hack it and even expand it via interconnecting doors to the room next door.

But there are some things you just shouldn't do in your cruise room.

Sorry, folks, but it's not 100-percent "anything goes" onboard. Whether it's a safety issue (think lighting fires), a privacy issue (no hanky panky on that balcony) or a consideration issue (please don't blare the TV at 2 a.m.), you'll want to curtail certain activities in your cabin -- or the crew may kindly, but sternly, ask that you do so.

In case you're tempted, or simply don't know, here are 12 things we ask that you please not do.

Booked? Find your Roll Call to see who's sailing with you.

1. Smoke

Sorry, smokers, but on most cruise ships, you need to take a hike to get your morning nicotine fix. All cruise lines have banned smoking in cabins, and many have even banned smoking on private balconies. Cigarettes are a fire hazard -- ships have caught fire due to wayward ash -- and many people also consider them a public nuisance. Understandably, the cruise lines want to limit cigarette use onboard, while still offering smokers a few places to light up. So you'll need to head to a designated area of an upper deck or specific lounge when you need a smoke break.

Cruise Line Smoking Policies

2. Light a candle

Or iron your clothes. Or light incense. Or plug in the hot plate you smuggled onboard. (Why would you ... never mind.) You get the idea. Anything that involves fire or high heat is a hazard and a no-no. Just be thankful that lines are generally open to hair dryers and curling or flat irons these days. (Battery-operated tea candles add ambiance without open flame).

3. Plug a hairdryer into the shaving outlet in the bathroom

Speaking of hairdryers, it remains a mystery why you must blow dry your hair by the desk in your cabin, rather than in the bathroom, but that's where ship designers have put the in-cabin dryer and the appropriate outlet. There is one measly outlet in your bathroom, but it's for shaving only, and it does not accommodate the correct voltage for a hair dryer. Try it out, and you could blow a fuse, shorting out the electricity and making you persona non grata with your onboard neighbors.

Bathroom Hacks to Make Your Cruise Ship Cabin More Livable

4. Have an argument

You can be loud as you want -- whether in anger or having a little in-cabin recreation, if you catch our drift -- as long as you're cool with all your neighbors knowing your business. Cruise ship cabin walls are notoriously thin, and sound travels quite well -- especially through connecting or hallway doors. The polite thing to do is keep the volume down. Even if you don't need privacy, your shipmates don't really want to listen to your movie selections at 3 a.m. And when it comes to your balcony, remember that you can easily be seen as well as heard, so act accordingly.

Etiquette Tips for Sharing a Cruise Ship Cabin

5. Run around naked with the curtains open

Along the lines of "your cabin isn't as private as you think" comes our next cabin don't. Plenty of cruisers have gotten the shock of their life when they have stepped out of the bathroom, naked as a jaybird, to discover they were looking out at a crewmember cleaner, portside dock workers or even other cruisers (especially likely on river cruises where boats dock side by side). And if you can see them, well, they can see you, too.

Even if your curtains are closed, it's wise to throw on a towel or at least peek out the bathroom door since your cabin steward has a key to your room and you're not going to hear him knocking if you've got the shower running.

Nude Cruises: Questions We All Have

6. Leave the balcony door open

Ah, the bliss of letting the sounds of wind and sea lull you to sleep! You might want to prop open that balcony door as you sail, but cruise lines aren't so keen on the idea. For starters, the warm air coming in will cause your cabin's air-conditioning to work harder (unless you turn it down), wasting energy on the ship.

Plus, leaving the door open can have some unwanted side effects. We set off the smoke alarm several times on one sailing -- a mystery as there was no smoke or fire -- and were told that leaving the balcony door open can do that. Open your cabin door at the same time, and you create a wind tunnel in the cabin, which will send all your dining reservation notices, cruise ship dailies and art auction advertisements flying everywhere.

10 Things Not to Do on a Cruise Ship Balcony

7. Hang items to dry on the balcony

It's so tempting. Your wet swimsuits never dry as quickly as you'd like on that flimsy string in your cabin shower, and the warm Caribbean sun is beating down on your balcony just begging to be used. If you just draped a few tankinis over that deck chair, they'd dry in no time.

There are a couple of reasons why this is not a good idea. Forget those articles of clothing when the ship sets sail, and they could sail away themselves (an environmental faux pas) or end up in a puddle on your balcony floor. An unexpected rain shower or a scheduled balcony cleaning could result in your clothes getting wetter than they started. Plus, cruise lines don't like anything flammable left on balconies -- especially on lines where balcony smoking is A-OK. Best to dry your items on the retractable clothes line that's usually in your shower (a few portable laundry hooks help here too).

8. Make a mess

We get it -- you're on vacation and don't feel like cleaning up after yourself. But take it from us: A little tidying goes a long way to making cabin life more bearable. With minimal walking space in the room, leaving your high heels or daypacks lying about the floor can cause injuries during a middle-of-the-night trip to the loo, and dumping all your maps, brochures and plastic bags full of souvenirs on any available surface will take up valuable sitting space and lead you to waste precious vacation time searching for your cruise key card or shore excursion ticket.

A travel document organizer, where you can keep your papers and small electronics in one place, might be your new best friend.

9. Spray perfume

The ventilation system, especially in windowless cabins, can leave much to be desired. Douse yourself with Chanel No. 5 or the bathroom with your favorite floral scent, and your cabinmate might run into the hall, gagging for air. While strong scents aren't necessarily prohibited, we urge you to take a light touch to those spray bottles. (That being said, a small spritz of air freshener in the bathroom is usually welcome).

10. Steal the bathrobes or towels

Cruise ship cabin amenities are not ripe for the picking. Even if that bathrobe is just your size or the towels are super soft, or if you must have that coffee table book about the ship to add to your collection, think twice about slipping the item into your suitcase. You will be charged an inflated price for items that go missing.

If you want a souvenir from your trip, your money is better spent buying something new in the gift shop, rather than some used linens touched by hundreds of passengers before you. If you must have a freebie, take home the travel bottle of shampoo or the in-cabin pen.

What Can I Buy on a Cruise with $50 Shipboard Credit?

11. Tape something to the wall or door

Tape can leave marks or peel off paint, so please be respectful of the interior decor. If you must leave a note or decorate the cabin, no problem! Cabin walls and doors are metal, so throw some cute magnetic clips into your suitcase, and you can hang notes, daily newsletters, signs, streamers and the like throughout your room without damaging the paint job.

12. Hide items in the safe -- and forget about them

By all means, use your cabin's safe to store your cell phone, passport, extra cash and credit cards. But do not leave them there. Whether you completely forget to check or simply missed something stuck in a corner or the back of the safe, you will be cursing at the airport when you realize your photo ID has just departed for its second Mediterranean vacation.

If you're prone to forgetfulness, we recommend storing your valuables in your suitcase under the bed or someplace else where you'll remember them.

Theft on Cruise Ships: How to Keep Your Belongings Safe

Cruise Critic is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by promoting and linking to Amazon.com.