I didn't adjust the tips at all and we never walked into a dining room. I'm not a person who lives based on food - I was there for the experience of being on a ship , not eating on a ship. And yes, my son is very picky. If I go on a cruise alone or with another adult, of course I would eat in the dining room. But NOT doing so this time had no affect on my trip. Other than I came home a few pounds lighter than when I left home, due to all the walking up and down stairs - waiting for the elevators was an exercise in stupidity!
No one enjoys fantastic and healthy food more than I do, but it's not the center of my universe, and should not be the focus of a cruise.
I did bring back pizza for us a couple of times from the Bistro as well as a delicious burger for me and I used trays that were provided.