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.
Crazy Awesome: The Tommyknockers and their affected Havenites initially play this straight, but then deconstruct it. Their abilities allow them to create crazy awesome things like flying tractors, typewriters that operate via telepathy, and a water heater powered by a small nuclear reactor-many of them by using mere D-cell batteries as the power source. However, the Tommyknockers' technological prowess is hindered by their psychosis (meaning that the "Crazy" part keeps them from being Awesome for long) and doesn't permit them to really use their abilities in the long run. The affected Havenites have a little better luck as they can devise efficient uses for this knowledge, but often overlook little details (such as the use of a DC converter) and succumb to the same psychotic bents.
Crosses the Line Twice: While the scene itself is pretty unpleasant, there's just something stupidly amusing about how Gard screams "Arriba, arriba!" as he charges with an umbrella.
For Gardener, the Tommyknockers cross it, when he finds out what's in Bobbi's shed. They keep people locked up in shower cabinets filled with some green liquid, attach cables to their brains, and suck the energy out of them; a long, incredibly painful process. He's especially freaked out to discover Bobbi's dog also hooked up.
In the miniseries, Becka's cheating husband has one after several earlier petty Kick the Dog moments: he leaves early from a search for a missing child to go sleep with his mistress since he knows that the search will keep his cop wife occupied. Read that again. He abandons a missing child to go cheat on his wife.
The scene in the Vet's office in the miniseries. It would've been alright in itself but the people waiting for the Vet had a Komodo Dragon, a Cobra and an Owl. It comes off as more silly than dramatic.
The scene with the writer throwing himself off the balcony.
The various effects on the Havenites as a result of the Tommyknockers' presence are quite unnerving. Various people find themselves bleeding uncontrollably, everyone loses their teeth, and, in the case of a few, their skin becomes transparent and they have tentacles where their genitals should be. Such things also count as examples of Nausea Fuel and Squick, respectively.
The violent acts the Havenites commit towards one another and others are also pretty unnerving. Such as one's giddy murder of two investigating policemen by obliterating them with a green light from his makeshift bazooka, and how another casually forces a poker buddy to partially disintegrate himself before he sends him to Altair-IV to die, all over cheating him for pennies in past games.
The horrific fate of those trapped in the shed behind Bobbi's house, including her poor dog.