Inside cabins are the cheapest option. They are comfortable, but will have no outside view, unless they overlook an inner deck on the ship. If you just want a pleasant room to sleep in this is a good option.
Ocean view cabins are like inside cabins but with a window view over the ocean.
Balcony cabins have a balcony on the outside of the ship. Some find this quite appealing, but it will cost more. And the balcony is not really private.
Suite is a much larger room with a balcony. You will pay more for this.
Some people prefer the ship cabin with the balcony. That balcony does have a great view, fresh air and the cabin is slightly larger. But it will cost at least 25% extra.
Most of the cruise will be spent outside the cabin, where there will be plenty of fresh air and a lot of great views. Do you need this in the cabin too? Most of the time the cabin is just for sleeping.
Casinos on ships are in international waters, so they are not covered by the same legal restriction that cover other betting establishments. Your chance of actually making money is very small.
If you miss the departure the ship will not wait.
Ships run on a budget and fuel considerations. They cannot afford to wait.
Crime still exists on cruise ships
There are a lot of people on a cruise ship, and there will always be a few who are dishonest. Cruise ships will have security, but not police. So there is little incentive for them to worry about theft, only passenger safety. They will protect the cruise ship reputation over the interest of the passengers. The usual laws do not apply in international waters.
Everybody gains weight on a cruise
The food is laid on, it’s a vacation, and you have already paid the money. Expect to put on weight.
Many cruise ships have a single power point, which makes charging all the devices a slow process. Bring a power board.
There are TV monitors watching almost every space of the ship outside the cabins.
Itinerates change all the time.
The ship may miss a port because of weather, local conditions or some other reason beyond their control. There is no compensation, the cruise will just go on as normal.