These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Harsher in Hindsight: The reverend of Nilbog's cult-like church bears an uncanny resemblance to David Koresh, the leader of the Branch Davidian cult that was assaulted during the Waco Siege, which the film preceded by three years. Even more harsh is the fact that he ends up being killed by being set on fire by the family.
Genius Bonus: Probably unintentional, but there are quite a few echoes of Christina Rossetti's poem "Goblin Market" present, particularly in how the goblins try to corrupt people by feeding them plant matter, and how homoerotic expressions of family values are the solution to defeating them. In both works, the goblins seem to represent an outsider threat to the status quo.
A double example can be found during the sermon at the Church. It's funny enough hearing the Preacher hammily ranting about "smelly bladders", but look carefully at the General Store Owner when hemorrhoids are mentioned. He puts his hands between his legs and squeezes them together.
Ho Yay: Drew sees Elliot and Brent sleeping in the same bed, with their shirts off.
Elliot (after Holly hits him in the groin): Are you trying to turn me into a homo? Holly: It wouldn't be too hard!
The film also seems to believe that "homosexuality" and "castration" are synonymous.
The entire plot thread regarding Drew's quest for milk (it would be milk, wouldn't it?) is laced with a disturbing, pseudo-rapacious homoerotica.
Elliot and his friends' relationship seems to consist entirely of Have I Mentioned I Am Heterosexual Today?, which is sort of negated by them running around in their underwear, sharing beds, and not being able to be without each other even for a couple days.
Les Yay: Creedence tells the mom that she finds Holly to be "appetizing" and "provocative." Strangely, the mom doesn't really react to this.
And neither does Holly.
Creedence: Hello, beautiful.
Holly: Hi. (Leaves without another word.)
Nightmare Retardant: See, the notion of people turning into plants could have been A-Grade Body Horror. But the effects are pretty bad and the dialogue is even worse, so it's hard to care.
Padding: The sequence where Creedence begs for more power, turns into a Hot Witch, then completely wastes her new powers seducing minor secondary character Brent with a corncob. She uses up her powers, doesn't even kill the guy, and none of this has any relevance to the rest of the movie whatsoever.