Each region has different foods. The south loves their BBQ and there is roughly one style per state in the south (the Carolinas and Texas have multiples), and each is fiercely defended as the best. (Shout-out to Owensboro mutton!)

Hotdogs and how they are served are another fight. Chicago, NY, Seattle, etc. have distinct styles and are eaten enough at lunch that folks become very protective of their mid-day rituals.

Soda/pop/soft drink flavors are also weirdly regional.

And none of these factor in the folks in the underrepresented areas like Hawaii, Alaska, etc. I can't even find info on food preferences for PR, Samoa, Guam, etc. Actual fruit and pork are big flavors that get their own treatment but aren't acknowledged as American, like Kalua pork or Taxi soda.

American is like a bunch of different regions that share a currency. Each has its own unique perspective on food and drink.