There are some foods it depends on how they’re served. Bananas for example. If they are in the peel, hands are OK, if they are mixed with mashed strawberries, or in bananas foster or something like that, I’d prefer a fork. Or soup, I don’t mind if you drink the broth out of the bowl, but digging the noodles out with your fingers is another story! There are SOME exceptions to my “anything as long as it’s not messy rule”, like buffalo wings, that’s what the wet naps are for. Pizza I’ll usually eat w/ my hands unless it’s really sloppy pizza that’s just gonna fall apart, then I’ll use a fork. Or olives, if I want to take them out of the jar and they’re in brine, I’ll probably use a spoon to dig it out, but I’ll probably pick it off the spoon with my fingers and eat it. I’m thinking the liquid to solid ratio is the most important factor, and the only exceptions are if the item is contained in something (like the soup in a bowl or cup where you’re not actually putting your fingers in the liquid). Sliced cheese = fingers, spray cheese = cracker. Just basically I think the real defining line is common sense.