I am an avid Carnival cruiser,although I haven't cruised extensively on other cruise lines. Carnival is ,in my opinion , not only the lines name but their philosophy in decor. These ships evoke a festive atmosphere much like mardi gras in New Orleans or Carnivale in Rio. They are not elegant or sophisticated by anyones standards, but they do to tend to help relieve inhibitions and evoke relaxation much more readily than their " stuffier" competition. Carnival has carved a niche into the cruise community unlikely to be equaled. After all we all have different tastes in vacations, as an example, look at Disney and the range of accommodations they provide.
most of all remember "A bad day of cruising beats a good day at work"