Invert the condition when filtering on unique values

[adimascio]

If I have 3 unique values "A", "B" and "C" in my column and I unclick on "A" and "B" to keep only "C", I expect the filter condition being generated to be value equal C rather than value not in (A, B)

[davinov]

Are you sure this is what we want ?
Imagine a collection with a great number of unique values. When I uncheck one of these values, I would expect the app to understand "I want to exclude this values from the result", and not "hardcode" all the other values as included.
This seems typically userful for null, 0, N/A or "Total" exclusion, when the other values are all relevant.

Moreover, in your example, there is a way to generate "value equal C" and not value "value not in (A, B)". The way is to hit "uncheck all" and then check C. If we remove that possibility, there will be no way left to generate not in conditions from the filters.