Quick watch this and come back. Don't worry, I can wait.
Back? Good, now we can talk.
Why is this so funny? The SNL skit follows the standard "premise-setup-punchline" comedy formula perfectly. The premise that Andy Samberg is a beloved DJ combined with the setup that he doesn't even need to try anymore is funny enough as a standalone topic. Through his inattention he demonstrates that he's infallible, leading him to increasingly distracting tasks. It's taking the common (and very true) notion that once the DJ hits play, he doesn't really need to do anything. But that's not the actual punchline, which happens next: Andy finally "drops the bass," and it gets "Turned Up to Death", murdering everyone.
In music, horror, comedy and design the unexpected kills. Throughout our lives we find that the unexpected plays out too much celebration. Without the unexpected laughs, scares, or musical drops we live in a world of monotony. Through these contrasting high and low points we create peaks and valleys in everything, almost to an unheard flow of music. Without it we would live incredibly boring lives. But we can't live as adrenaline junkies, trying to increasingly one-up ourselves. It's undoable and it would be a complete mess, much like terrible electronic dance music (EDM).
The usual mess of EDM that's released comes from amateur and novice artists creating a cacophony of noise. The most popular artists understand a rhythm and flow, creating a resounding beat that finally leads to a crescendo and a climax. Expecting the song to decrescendo, it suddenly "drops" with major changes in rhythm and tone in unique and unexpected ways to better contrast the repetitive chorus, creating a killer song.
Speaking of killers, horror movies find popularity much in the same way by overturning expectations. Consider the critically panned Friday the 13th series and any M Night Shyamalan movies as prime examples of repetition without any extremes. Sure, the slasher genre is pretty extreme just for the violence, but the 12 Friday movies follow the exact same plot: here are some people at camp, they die, Jason is defeated, roll credits. Sure, there are some scares, but the plot remains steadfast and unchanging. On the other hand, M. Night Shamalyan's terrible movies follow the exact opposite, creating the internet meme, "What a twist!" because of his increasingly ridiculous, absurd, and out-of-nowhere surprise endings.
But it's that twist that matters in design. The greatest masters create a rhythm of expectations, through a variety of means, and finally an unexpected twist that breaks those established rules. Compare these three series. Series A establishes an easily recognizable pattern, a basic grid with some variances in sizes. Series B doesn't establish a pattern, being completely random shapes and colors.
Something magnificent happens when unique elements from series B are inserted into A: a special emphasis is added by breaking the established pattern. Even minor variations from the established order becomes a momentous change giving unimaginable power to that simple, minute change.
Series A is boring. Series B is random crap. By mixing the two concepts together you create a unique creature that, at the same time, is ordered and special. Much like music, comedy, and horror, adding something different to a design creates something stronger—something that is really killer.