This was my first cruise but my friend has been on several, and admitted that this was by far his worst experience. The food was DISGUSTING (and neither of us are picky) and the hours of operation for most of the food options weren't that long. There aren't a lot of interesting activities, especially if it's raining. We walked around, desperate for something to do, but just weren't interested in the towel folding demonstrations and Puffy Eye seminars on the agenda. I observed a lot of the crew and, with the exception of two, they all seemed empty and miserable. They said as little as possible and were even rude to guests that were just trying to be friendly. The man who serviced our stateroom was super friendly though, although I was shocked they don't throw away trash -- he even kept taking trash out of our trashcan, but not sure if he was just being funny.
I enjoyed Cozumel and heard the some of the shore excursions were fun. We had a stateroom with a window, but it was too dirty to really see well out of it, so I wouldn't bother with the money. Just really not worth the cheaper price to be stuck in the ocean on a very rocky ship with a miserable crew and nothing to do. Would not recommend Carnival!
The lines went quickly, but the workers were just very unfriendly/rude and didn't help start the cruise off right for sure.
The people at Cozumel were friendly and the shopping and drinks were good.