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.
There's a certain sound effect that really wigs people out who hear it.
The fingernail snapping off, and its sound effect; also counts as Nausea Fuel
Rewatch Bonus - A lot of off-hand remarks made during the movie take on a new twist when you know what's really going on, such as how Frank keeps going on about what a decent neighborhood it is that they all live in.