Analysts typically conduct one-shot case studies on unique events of history.

The concept of U (for upper-class British usage, as opposed to non-U, or everything else) was introduced by Alan S. C. Ross (1954) and was taken up by Nancy Mitford (1956), becoming for a time something of a parlor game in which the participants tested themselves and everyone else for signs of U and non-U status.

a housewarming gift

No sin goes unpunished here, no joy unguilted.