You'll get no argument from me on that one, said the red-haired green eyed gal : )
And you forgot the mayonnaise vs. ketchup on hamburgers and the over or under on the great toilet paper roll controversy.
Computers, firearms, cars/trucks/motorcycles, etc. You can start a "spirited discussion" about anything people are passionate about. As a good friend pointed out - people tend to be really passionate about other people and food. She is adamant about this link and we've discussed it at length. She makes a far better case for it than I could ever summarize here.
Red and green eh? Sigh... ;-)