When I first started cruising I was Loyal to Royal. I tried a Princess and the food was horrible (This was 20 years ago when I was eating a lot and often, you know, youth) I avoided Princess for 20 years until a group cruise and it was a great cruise with good MDR food and service so Princess is back on my preferred list.
Later in my cruising history I tried NCL, My TA advised me against it but it was a good itinerary and price so I gave it a try. Worst cruise I have been on. I avoided NCL after that until I got a killer price on a re positioning cruise on the Pearl ($350.00 for 7 nights). That cruise was good, not great but good for the price still typical bad food and service of NCL in the MDR IMHO, Then there was a cruise for Charity that was changed from RCI to an NCL ship kind of last minute (RCI pulled all ships out of CA due to issues in Mexico), I only went because it was a fund raiser for a good cause and friends were also going. Again Bad food, bad service and problems with cabins, 3 of us out of a group of 50 had to complain and get cabin changes because of issues in our original cabins. Now I avoid NCL.
How many bad or jusr so-so cruises does it take until you stop cruising a cruise line ?