Danny Webster’s review published on Letterboxd:
Director: M. Night Shyamalan (Final film)
No matter the point of a film, whether it be serious messages or homage to B-movies, it has to at least entertaining. And whilst The Happening certainly is that for roughly half the running time of the film, I suspect there were two possible reasons to why it became what it is.
1. Shyamalan genuinely wanted to create a homage to B-movies of the '60s, and hired two awful actors in Mark Wahlberg and Zooey Deschanel to try and make it convincing. Shyamalan forgot to mention that he wanted this from the actors, and let them do their thing, which was to (on first take) act horribly and he would then tell them they were great. This would lead to eventually Wahlberg calling the film shit two years later and then shouting "Fuck Plants!" in various interviews. Unbeknownst to him, this would cause a chain reaction and plants would hear these insults, be offended and release toxins into the air which make us commit suicide. The point of this film? M. Night Shyamalan wants to end the world.
2. The other possibility is that M.Night Shyamalan went straight with the film, believing it to be a truly horrifying premise and hired two relatively popular "actors" for commercial purposes. He wanted to make us believe in the story and thus had Wahlberg talk to a plastic plant, which to everyone's horror performed better than him. This panicked Shyamalan and just before the film's release, in a moment of trying to save his reputation he exclaimed that the film was a "good homage to B-movies" which in turn would explain the horrific but hilarious performances. Not only does this save the massive ego of Shyamalan from being damaged he is able to maintain that he is smarter than the critics who claim the film isn't very good - because his intentions were always for it to be terrible - true to the reputation he has obtained as a film-maker.