I have found that most of the people that come and complain sound like they did not bother to read the cruise contract they agreed to when they booked the cruise. Did not read the FAQ section on carnival.com and never bothered to read about they type of rate they were booking, ie the early saver , carnival has a FAQ section just to explain that rate.
What you will find is that the people that have a great time on their cruise are the lucky ones that do their homework and have found websites like this to ask questions.
The big thing is that everyone needs to remember that a vacation is still real life and not everything will be perfect. You just have to know ahead of time how to handle the problems that do come up.
I hope everyone has a safe and wonderful cruise.