A fantasy ontology refers to a fantasy that is unsatisfiable in the real world due to a carving up of processes that are inseperable in reality. A whole genre of examples arises from conceptions of "the perfect X" making us happy, where X can be a relationship, job, physical item, group membership etc. ignoring the variety of prerequisites, responsibilities, and outright impossibility some of those may require.

This tendency can be adaptive when it leads us to check whether some particular unpleasantness is actually necessary, but often runs haywire when left as a tacit rather than explicit analysis.