Food
Between human cultures, food is the great equalizer. It is the same with dragons who come into Grabon’s territory. Dragons may not be familiar with human customs of hospitality and the offering of food and drink, but they can certainly appreciate it.
The idea that most dragons do not eat for texture or flavor, but rather to choke down the necessary nutrition came to me because I know people who are not taste montivated or even food interests most of the time. Bing a nice round person I have some difficulty relating, but I know how uninterested they are, unless confronted with something that captures their attention.
My stories highlight that difference because even when humans are unimpressed with offerings, they are not unaware of their tastebuds. Dragons learn to ignore the taste of everything as youngsters, choking down pieces of meat. Their world opens when they discover the pleasant and interesting flavors of prepared foods.