- Creator Killer: M. Night Shyamalan was already feeling it after Lady in the Water became his first bona fide failure since he became famous, but this film only made him that much more of a laughingstock.
- Deliberate Flaw Retcon: This article argues that the film is actually a work of genius, the 'flaws' being deliberately worked in to subvert B-Movie Sci-Fi Horror tropes.
- Old Shame:
Wahlberg: …Fucking trees, man!
- Mark Wahlberg has admitted that this is one of the worst films he has ever done.
- Chris Stuckmann related an anecdote about when he attended a screening of The Cabin in the Woods, which starred Kristen Connolly, aka the friend of the knitting needle woman from the opening scene. When he asked about her experience on The Happening, Stuckmann noted that Connolly's expression turned sour.
- Similarly Named Works: There was another film called The Happening released in 1967, and most of the people who have seen it also find that one terrible.note If it's remembered at all now, it's for being the screen debut of Faye Dunaway, and for its hit title song by The Supremes.
- What Could Have Been: Amy Adams turned down the role of Alma.