In fact, I refuse to eat at McDonald's, and avoid all those burger chains as much as I can. I make a better burger anyway. ;)
I find that if I go out for lunch I'm tempted to eat a larger portion, feel overly full, and then experience a sort of food-coma. But when I make my own lunch, I eat a smaller portion, don't feel weighed down, and remain productive. I wonder how many calories my homemade, no mayo, toasted roast beef & muenster sandwich with olive oil-sauteed mushrooms and onions with marinated spinach and tomato has.