I think, grilled cheese is universally liked. It has changed over the years. When I was a kid, grilled cheese was a slice of American cheese with a slice of tomato, grilled. It was delicious then but now it has taken on a new life. Grilled cheese has many additions. My favorite is avocado. Although, after eating the caramelized onions and spinach on this one, I may have a new favorite.
I also think that people often think of tomato soup as an accompaniment to the sandwich but I tried potato soup and it was a yummy combination.