I'm one of those that tends to eat my food in a certain order. I have a friend who picked on me about it after he first noticed I did it. I generally start with my least favorite item or with something that needs to be eaten soonest because it will get cold or melt. In the Cracker Barrel example given, I would eat the green beans first because although I like greenbeans, they wouldn't be my favorite item on that plate, plus vegetables get cold fastest and don't taste as good once they're cold. Then I would eat either the macaroni or mashed potatoes depending on which item I was most in the mood for that day or which looked the best. I'd eat the chicken last because it's the main part of the meal. Plus, fried chicken can be too hot on the inside yet when it's served so by the time I eat everything else, it will be cool enough to bite into without the juices burning me.
I will go back to an item if I don't eat all of it at once.