This is a time where I don't need to tell you why dissecting what is and isn't funny is in and of itself both complex and dumb. That is my intro, because What We Do In The Shadows didn't work for me (although I wager it will work for most other people, given the response from both word of both and the group I was with), and this is my attempt to figure out why.
What We Do In The Shadows is a New Zealand comedy (from the people behind Flight of the Conchords) about vampires presented as a reality-style documentary. Think The Office or a Christopher Guest movie with less one-on-one interviews. Vladislov, Viago, Deacon and Petyr live together in a big typical mansion, and a lot of the early movie is contrasting the supernatural with the mundane of petty household complaints mixed with Petyr – the silent, intimidating Nosferatu model – for the odd physical gag.
This was where I started to sense I wasn't getting out of the movie what others were (laughter around me, another clue). Every word I can think of here sounds condescending, but a lot of the jokes around the house felt easy and ancient, taking from the Addams Family/Munsters (no hate) school of “this is funny because vampires do this,” and none of that early stuff worked for me.
The closest movie I can compare it to, I believe, is Aardman Animation's The Pirates: Band of Misfits (another comparison to something I find very funny). Aardman (Wallace and Gromit) uses some of the most worn, cheesy jokes in all their work. Why do those land? Perhaps for two reasons. One, there's always something I like about Aardman protagonists. They might be bumbling and righteously prideful or just dumb or what have you, but there's something earnest and reason is given for me to be invested, which I didn't get out of any of the vampires in What We Do In The Shadows. Nick the vampire, introduced eventually to act as the new guy, worked as a serviceable straight man but the humor wasn't coming from his direction. Number two, Aardman tends to use those hokey jokes almost as a faint before hitting you with the big joke. It lures you into a sense of security before dropping the funny. What We Do In The Shadows felt especially straight forward with little in way of surprise, which is a cornerstone of comedy.
That isn't to say it fell flat entirely. Stuart, the human friend of Nick the vampire, who everybody liked for no reason, was the star of the movie as far as I'm concerned. Whereas Nick the vampire was a regular Joe straight man, Stuart somehow was a much more interesting even more regular Joe as this innocent I.T. guy. His loving simplicity made for the best scenes, when this band of ineffective vampires were forced to protect their vulnerable friend against actual threats. This only happened twice, and I would have liked to have seen this played with even more (like the dog that always ends up in the villain's path of destruction in The Powerpuff Girls), but his journey was fun to watch nonetheless.
This does highlight a problem I had, though, which is that every interesting plot move happened late in the film. The aforementioned Stuart situations, a group of werewolves doing more than being introduced as another band of doofuses (led by the hilarious Rhys Darby), Vladislav's old love, Viago and his nemesis The Beast (with a quick whimper of a resolution)... I think some very funny things happened later on, but I was already checked out of the movie/these characters by then, and I didn't have the emotional attachment to carry me through, so when they did or didn't happen, it had no punch.
I'm also not sure the movie knew what kind of budget it wanted to be seen as, because the visual effects, when used, looked outstanding. They're in WETA country, after all. But it was sparse and left me wanting to see it either utilized more or not at all. Or even to tease the audience, to get them expecting an effects-heavy spectacle and pull the rug out from under them, or vice versa (effects vice versa, not the rug. Don't pull the rug out from under filmmakers). The biggest effects I can think of were used not as jokes but simply to look cool in the vampires' only moments of competency, which was confusing when they were incompetent. This is a case where I think I would have liked them to have had less money so they would have needed to find creative ways around certain spots.
While I didn't connect with the characters, don't let that stop you from seeking it out for yourselves. What We Do In The Shadows is unrated, sometimes vulgar and a little bloody, but still a live-action cartoon with an older sensibility that I wish explored more of its story edges and supporting cast and less its awkward, dundering housemates.
More than any other genre, comedy is subjective. Discussing Zombieland with a friend years ago, I listed detail after detail of why I didn't enjoy it, and all he had to say was “well I thought it was funny.” So, with What We Do in the Shadows, all I can say is: I didn't find it funny.