Niceness
Part of speech: noun
Definition: the quality of being nice an action that demonstrates that quality
Subtlety
Part of speech: noun
Definition: The quality or fact of being subtle.An instance of being subtle, a subtle thing, especially a subtle argument or distinction.An ornate medieval illusion dish or table decoration, especially when made from one thing but crafted to look like another.
Example sentence: Human subtlety will never devise an invention more beautiful, more simple or more direct than does nature because in her inventions nothing is lacking, and nothing is superfluous.