ETA: take the slapping scene at the end. The basic gag - the slap expels the ghost, but the slapper doesn't realize it, so she slaps again - is promising. A clever way to visualize that would have been to show the ghost get slapped downwards, right through the floor and into the room below. Cut to McCarthy moaning, which Jones misinterprets, so she slaps again. Funny. Not funny, however, is what we get: a distracting cut to outside the building, with a hugely obvious "the ghost is leaving leaving" effect, followed by McCarthy saying an obviously non-possessed, cliched "that's gonna hurt" line, followed by Jones slapping again.