This is so true. I keep trying to "justify" what I'm spending on my November
DCL trip by ensuring that I've included every possible expensive on Carnival (which we're sailing the following week) including stuff we probably won't end up paying for (I have included the steakhouse on Carnival - we enjoy the MDR on Carnival so I just can't see going there) and of course our gambling money (possible that we won't spend it all or that we could come home with some).
Eventually I just had to give up and say - "it costs what it costs and you're paying it so shut up and feel good about it or you're not going to enjoy yourself." (and yes, I frequently have to yell at myself to spend money on myself).
We'll have a great time on the Disney Fantasy, and then we'll have a great time on the Carnival Magic.