In English, when people say "that is so good" instead of "this is so well" when referring to food that is right in front of them or in their hands, it is a common linguistic pattern and a matter of idiomatic usage. The choice between "that" and "this" in this context is influenced by the way English speakers commonly refer to objects and experiences.
The use of "that" is often associated with something that is a bit more distant, both physically and psychologically, from the speaker. It can create a sense of detachment or objectivity. When people refer to food as "that is so good," they might subconsciously treat it as an external object, even if it's right in front of them, as if they are observing it from a slight distance.
On the other hand, "this" is used for objects that are more immediate, close, or emotionally connected to the speaker. By saying "this is so well" to describe food, it might imply a level of formality or distance that is not typically associated with the casual and personal nature of discussing food.
Additionally, "good" and "well" have different grammatical functions and are used in distinct contexts. "Good" is an adjective that describes the quality or taste of the food, while "well" is an adverb that modifies verbs, adjectives, or other adverbs. So, "good" is more appropriate for describing the taste or quality of food, whereas "well" would be more fitting in sentences related to cooking or food preparation.
In everyday speech, language tends to follow patterns and conventions that might not always adhere strictly to grammatical rules. Expressions and phrases become idiomatic over time, and "that is so good" has simply become the more commonly used and accepted way to express appreciation for food in casual conversations.
Languages evolve, and certain linguistic choices become deeply ingrained in the way people communicate. These tendencies can vary across different languages and cultures, and they are an interesting aspect of how languages shape and adapt to human expression.